The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional dr...The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic surface.The electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic force.Positively or negatively charged droplets can also be driven by TET based on electrostatic attraction and repulsion.TET enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(e.g.ethanol with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed system.Various droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.展开更多
We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures,and predict the changes of...We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures,and predict the changes of ablation morphology and lattice temperature.For investigating the effect of sample temperature on femtosecond laser processing,we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model.The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises.When the sample temperature rises from 300 K to 600 K,the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation,and the ablation depth increases by 20%.The simulated ablation depths follow the same general trend as the experimental values.This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.展开更多
The development of energy storage devices with high energy density relies heavily on thick film electrodes,but it is challenging due to the limited ion transport kinetics inherent in thick electrodes.Here,we report on...The development of energy storage devices with high energy density relies heavily on thick film electrodes,but it is challenging due to the limited ion transport kinetics inherent in thick electrodes.Here,we report on the preparation of a directional vertical array of micro-porous transport networks on LTO electrodes using a femtosecond laser processing strategy,enabling directional ion rapid transport and achieving good electrochemical performance in thick film electrodes.Various three-dimensional(3D)vertically aligned micro-pore networks are innovatively designed,and the structure,kinetics characteristics,and electrochemical performance of the prepared ion transport channels are analyzed and discussed by multiple characterization and testing methods.Furthermore,the rational mechanisms of electrode performance improvement are studied experimentally and simulated from two aspects of structural mechanics and transmission kinetics.The ion diffusion coefficient,rate performance at 60 C,and electrode interface area of the laser-optimized 60-15%micro-porous transport network electrodes increase by 25.2 times,2.2 times,and 2.15 times,respectively than those of untreated electrodes.Therefore,the preparation of 3D micro-porous transport networks by femtosecond laser on ultra-thick electrodes is a feasible way to develop high-energy batteries.In addition,the unique micro-porous transport network structure can be widely extended to design and explore other high-performance energy materials.展开更多
Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conducto...Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness.Despite research efforts,challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance.To address these challenges,we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method.Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber(1.03 kPa),our actuator exhibits an excellent deformation angle(265.25?)and actuation bending angular velocity(284.66 rad·s^(-1)).Furthermore,multiple actuators have been combined to build an artificial gripper with a wide range of functionalities.Our actuator presents new possibilities for designing small-scaleartificial machines and supports advancements in ultrafast soft and miniaturized robotics.展开更多
Objective:To evaluate the clinical effect of full femtosecond laser surgery in the treatment of myopia patients.Methods:120 myopia patients admitted to our hospital from January 2022 to June 2023 were selected.Accordi...Objective:To evaluate the clinical effect of full femtosecond laser surgery in the treatment of myopia patients.Methods:120 myopia patients admitted to our hospital from January 2022 to June 2023 were selected.According to the random number table method,60 patients in the observation group underwent full femtosecond laser surgery,and 60 patients in the control group underwent femtosecond laser-assisted in situ keratomileusis(FS-LASIK)surgery.The clinical effects of the two groups were compared.Results:10 days postoperatively and 6 months after operation,the visual acuity level of the observation group was higher than that of the control group,the postoperative corneal asphericity coefficient and corneal full-thickness were lower than those of the control group,and the total effective rate 6 months after operation was higher than that of the control group(P<0.05).Conclusion:Full femtosecond laser surgical treatment can improve the postoperative visual acuity of patients with myopia,enhance the corneal asphericity coefficient(Q)and corneal full-thickness,and exert significant clinical effects.展开更多
Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere...Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere femtosecond laser irradi-ation in far field.By varying laser fluence and scanning speed,nano-feature sizes can be flexibly tuned.Such small patterns are attributed to the co-effect of microsphere focusing,two-photons absorption,top threshold effect,and high-repetition-rate femtosecond laser-induced incubation effect.The minimum feature size can be reduced down to~30 nm(λ/26)by manipulating film thickness.The fitting analysis between the ablation width and depth predicts that the feature size can be down to~15 nm at the film thickness of~10 nm.A nano-grating is fabricated,which demonstrates desirable beam diffraction performance.This nano-scale resolution would be highly attractive for next-generation laser nano-lithography in far field and in ambient air.展开更多
We report novel results on top-down percussion drilling in different glasses with femtosecond laser GHz-bursts.Thanks to this particular regime of light–matter interaction,combining non-linear absorption and thermal ...We report novel results on top-down percussion drilling in different glasses with femtosecond laser GHz-bursts.Thanks to this particular regime of light–matter interaction,combining non-linear absorption and thermal cumulative effects,we obtained crack-free holes of aspect ratios exceeding 30 in sodalime and 70 in fused silica.The results are discussed in terms of inner wall morphology,aspect ratio and drilling speed.展开更多
AIM:To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laserassisted phacoemulsification(FLACS).METHODS:This study enrolled patients with cataract combined with regular co...AIM:To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laserassisted phacoemulsification(FLACS).METHODS:This study enrolled patients with cataract combined with regular corneal astigmatism of>0.75 D,who underwent FLACS.Symmetrical arc incision was set at 8 mm diameter and 85%depth.The follow-up time was 3-24mo(4.92±3.49mo).Pentacam recorded the corneal astigmatism and higher-order aberration at pre-operation and post-operation.The changes in corneal astigmatism were analyzed by Alpins method.The correlation of astigmatism type,age,corneal horizontal diameter,corneal thickness,arc incision length,and correction index(CI)was analyzed,and the residual corneal astigmatism was compared with the residual whole eye astigmatism.RESULTS:Totally 79 patients(102 eyes)were enrolled,10 patients had corneal epithelial injury,1 patient occurred corneal epithelial hyperplasia.The corneal astigmatism was 1.23±0.38 D pre-operation,and decreased to 0.76±0.39 D post-operation(t=10.146,P=0.000).Corneal high-order aberration was 0.17±0.08μm pre-operation and 0.24±0.11μm post-operation(t=-5.186,P=0.000).The residual corneal astigmatism and residual whole eye astigmatism were no significant difference(t=-0.347,P=0.729).Using Alpin’s method,the following were determined:target-induced astigmatism(TIA)=1.23±0.38 D,surgeryinduced astigmatism(SIA)=0.77±0.45 D,difference vector(DV)=0.77±0.39 D,and CI=0.54±0.28.Age,astigmatism size,corneal horizontal diameter,corneal thickness,and arc incision length were not correlated with CI.The CI for against the rule astigmatism(ATR)was better than that for with the rule astigmatism(WTR;P=0.001).CONCLUSION:Femtosecond laser-assisted astigmatic keratotomy has better CI of ATR,but increase higher-order corneal aberration.CI is not ideal,it’s not a perfect choice if we pursue ideal correction effect.展开更多
This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LI...This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LIPSSs exhibited good properties as nanowires,with a resistivity almost equal to that of the initial ITO film.By changing the laser fluence,the nanowire resistances could be tuned from 15 to 73 kΩ/mm with a consistency of±10%.Furthermore,the average transmittance of the ITO films with regular LIPSSs in the range of 1200-2000 nm was improved from 21%to 60%.The regular LIPSS is promising for transparent electrodes of nano-optoelectronic devices-particularly in the near-infrared band.展开更多
Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable prope...Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable properties and functions to address the demands of ever-changing application environments that are becoming more intricate.Among many fabrication methods for stimulus-responsive structures,femtosecond laser direct writing(FsLDW)has received increasing attention because of its high precision,simplicity,true three-dimensional machining ability,and wide applicability to almost all materials.This paper systematically outlines state-of-the-art research on stimulus-responsive structures prepared by FsLDW.Based on the introduction of femtosecond laser-matter interaction and mainstream FsLDW-based manufacturing strategies,different stimulating factors that can trigger structural responses of prepared intelligent structures,such as magnetic field,light,temperature,pH,and humidity,are emphatically summarized.Various applications of functional structures with stimuli-responsive dynamic behaviors fabricated by FsLDW,as well as the present obstacles and forthcoming development opportunities,are discussed.展开更多
A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemi...A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.展开更多
The tunneling ionization (TI) is the most dominated ionization process in the production of terahertz radiation by two femtosecond lasers, although its validity above the ionization threshold of some gases is uncertai...The tunneling ionization (TI) is the most dominated ionization process in the production of terahertz radiation by two femtosecond lasers, although its validity above the ionization threshold of some gases is uncertain. In the present research, we employ a 1D fluid code to simulate the efficiency of the produced terahertz radiation by two femtosecond laser beams in air plasma. Two ionization models in the context of the TI process which are the Ammosov-Delone-Krainov (ADK) for noble gases and its developed molecular ADK (MO-ADK) model for molecular gases are intrinsically used to conduct this study. The main target of the present research is to examine the validity of these models Above-Threshold-Ionization (ATI) of these gases. For this purpose, we simulated the ionization rate and the power spectrum of the produced radiation, in addition we numerically evaluated the efficiency of the produced radiation as function of the input beams intensity at particular energy fraction factor, relative phase and initial pulse duration of these beams. These calculations conducted for a selected noble gas at varying energy levels and a chosen molecular air plasma gas at different quantum numbers. Numerical results near and above the ionization threshold of the selected gases have clarified that the ADK and MO-ADK model are successful valid to study the efficiency of the produced THz radiation at low energy levels and small quantum numbers of the selected gases, meanwhile, with any further increase in the energy level and the quantum number values of these gases, both of the ADK and MO-ADK are failed to correctly analyze the efficiency process and estimate its fundamental parameters.展开更多
AIM: To compare and calculate the 3-year refractive results, higher-order aberrations (HOAs), contrast sensitivity (CS) and dry eye parameters after small incision lenticule extraction (SMILE) and wavefront-gui...AIM: To compare and calculate the 3-year refractive results, higher-order aberrations (HOAs), contrast sensitivity (CS) and dry eye parameters after small incision lenticule extraction (SMILE) and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for correction of high myopia and myopic astigmatism. METHODS: In this prospective, non-randomized comparative study, 78 eyes with spherical equivalent (SE) of -8.11±1.09 diopters (D) received a SMILE surgery, and 65 eyes with SE of -8.05±1.12 D received a wavefront-guided FS-LASIK surgery with the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) for flap cutting. Visual acuity, manifest refraction, CS, HOAs, ocular surface disease index (OSDI) and tear break-up time (TBUT) were evaluated during a 3-year follow-up. RESULTS: The difference of uncorrected distance visual acuity (UDVA) postoperatively was achieved at lmo and at 3mo, whereas the difference of the mean UDVA between two groups at 3y were not statistically significant (t=-1.59, P=-0.13). The postoperative change of SE was 0.89 D in the FS-LASIK group (t=5.76, P=0.00), and 0.14 D in the SMILE group (t=-0.54, P=0.59) from lmo to 3y after surgery. At 3-year postoperatively, both HOAs and spherical aberrations in the SMILE group were obviously less than those in the FS-LASIK group (P=0.00), but the coma root mean square (RMS) was higher in the SMILE group (0.59±0.26) than in the FS-LASIK group (0.29±0.14, P=0.00). The mesopic CS values between two groups were not statistically significant at 3y postoperatively. Compared with the FS-LASIK group, lower OSDI scores and longer TBUT values were found in the SMILE group at Imo and 3mo postoperatively. With regard to safety, no eye lost any line of CDVA in both groups at 3y after surgery. CONCLUSION: Both SMILE and wavefront-guided FS- LASIK procedures provide good visual outcomes. Both procedures are effective and safe, but SMILE surgery achieve more stable long-term refractive outcome and better control of early postoperative dry eye as compared to FS-LASIK.展开更多
Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically...Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty(LTK)in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery(FLACS).This is the first report of both procedures combined simultaneously,with or without history of LTK.Case Description:A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004,with subsequent surgically induced high corneal astigmatism,and with age-related nuclear cataract of both eyes.IOL master demonstrated+7.71 diopters of astigmatism at 163 degree right eye and+3.29 diopters of astigmatism at 4 degree left eye.After extensive discussion of the risks and benefits,the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions(RIs)and toric IOL(Alcon SN6AT9)right eye;FLACS with toric IOL(Alcon SN6AT7)alone left eye.At 2-year follow-up,uncorrected visual acuity was 20/30 right eye,20/25 left eye.His best corrected visual acuity was 20/25(+0.25+1.00 axis 21)right eye and 20/20(plano+0.25 axis 90)left eye;his best corrected near visual acuity was J1+with add+2.50 diopters right eye and left eye.Conclusions:Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery.An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9,in our case,simultaneously,which can achieve an excellent long term visual outcome.展开更多
AIM: To compare the complication rate of femtosecond laser-assisted cataract surgery(FLACS) and traditional phacoemulsification for the first 18 mo of FLACS use at a private surgical center in Hawaii.METHODS: A retros...AIM: To compare the complication rate of femtosecond laser-assisted cataract surgery(FLACS) and traditional phacoemulsification for the first 18 mo of FLACS use at a private surgical center in Hawaii.METHODS: A retrospective chart review was conducted from January 2012 to June 2013. The first 273 consecutive eyes receiving FLACS and 553 eyes receiving traditional phacoemulsification were examined.All surgeries were performed at a single surgical center in Hawaii. The presence of intraoperative complications was used as the main outcome measure. Approval was obtained from the institutional review board of the University of Hawaii.RESULTS: The overall complication rate for FLACS was 1.8%, while that of the traditional procedure was5.8%(P 【0.05). A majority of the surgeons(80%) had a lower complication rate while using FLACS.CONCLUSION: FLACS is comparable in safety, if not safer, than traditional cataract surgery when performed by qualified cataract surgeons on carefully selected patients.展开更多
AIM:To evaluate the possible differences in visual quality between small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(FS-LASIK)for myopia.METHODS:A Meta-analysis was performed...AIM:To evaluate the possible differences in visual quality between small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(FS-LASIK)for myopia.METHODS:A Meta-analysis was performed.Patients were from previously reported comparative studies treated with SMILE versus FS-LASIK.The Pub Med,EMBASE,Cochrane,Web of Science and Chinese databases(i.e.WANFANG and CNKI)were searched in Nov.of 2016 using Rev Man 5.1 version software.The differences in visual acuity,aberration and biomechanical effects within six months postoperatively were showed.Twenty-seven studies including 4223 eyes were included.RESULTS:No significant differences were observed between SMILE and FS-LASIK in terms of the proportion of eyes that lost one or more lines of corrected distance visual acuity after surgery(P=0.14),the proportion of eyes achieving an uncorrected distance visual acuity of 20/20or better(P=0.43),the final refractive spherical equivalent(P=0.89),the refractive spherical equivalent within±1.00diopter of the target values(P=0.80),vertical coma(P=0.45)and horizontal coma(P=0.06).Compared with the FSLASIK group,total higher-order aberration(P〈0.001)and spherical aberration(P〈0.001)were higher and the decrease in corneal hysteresis(P=0.0005)and corneal resistance factor(P=0.02)were lower in the SMILE group.CONCLUSION:SMILE and FS-LASIK are comparable in efficacy,safety and predictability for correcting myopia.However,the aberration in the SMILE group is superior to that in the FS-LASIK group,and the loss of biomechanical effects may occur less frequently after SMILE than after FS-LASIK.展开更多
AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microke...AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intendedfiap thickness was 110 mu m and 160 mu m respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45 degrees and 135 degrees meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43 +/- 4.70 mu m, while 125.90 +/- 17.50 mu m in the Hansatome group. The difference between the actual and the expectedfiap thickness was 5.61 +/- 3.84 mu m and 31.52 +/- 12.27 mu m, respectively. The Hansatome group had presented a statistically significant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.展开更多
AIM: To compare the outcomes of laser in situ keratomileusis (LASIK) performed with a femtosecond laser (Femtec, Technolas Perfect Vision GmbH, Germany) versus a mechanical microkeratome (Hansatome, Bausch and Lomb, U...AIM: To compare the outcomes of laser in situ keratomileusis (LASIK) performed with a femtosecond laser (Femtec, Technolas Perfect Vision GmbH, Germany) versus a mechanical microkeratome (Hansatome, Bausch and Lomb, USA) for the correction of myopia and astigmatism. ·METHODS: In this retrospective study, patients who had undergone LASIK using the 80 -kHz Femtec femtosecond laser were compared to age- and refraction- matched patients in whom the Hansatome microkeratome was used. Refractive and visual results 1 month and 3 months postoperatively, and complication rates were compared between the two groups. ·RESULTS: A total of 280 eyes were analyzed (140 in each group). At 3 months postoperatively in the Femtec vs Hansatome group, spherical equivalent refraction was within ±1.00D of emmetropia in 140 vs 138 eyes (P = 0.498), the cylinder was within ±0.50D in 137 vs 139 eyes (P =0.622), and the UDVA was 20/20 or better in 136 vs 137 eyes (P =0.724), respectively. There was no statistically significant difference in the complication rates between the two groups (P =0.099). ·CONCLUSION: LASIK performed both with Femtec femtosecond laser and Hansatome microkeratome achieved satisfactory refractive and visual results at 3 months postoperatively, without significant differences in efficacy, safety, and complication rates between the two procedures.展开更多
Currently,supra-wavelength periodic surface structures(SWPSS)are only achievable on silica dielectrics and silicon by femtosecond(fs)laser ablation,while triangular and rhombic laser induced periodic surface structure...Currently,supra-wavelength periodic surface structures(SWPSS)are only achievable on silica dielectrics and silicon by femtosecond(fs)laser ablation,while triangular and rhombic laser induced periodic surface structures(LIPSS)are achievable by circularly polarized or linear cross-polarized femtosecond laser.This is the first work to demonstrate the possibility of generating SWPSS on Sn and triangular and rhombic LIPSS on W,Mo,Ta,and Nb using a single linearly polarized femtosecond laser.We discovered,for the first time,SWPSS patches with each possessing its own orientation,which are completely independent of the light polarization direction,thus,breaking the traditional rules.Increasing the laser power enlarges SWPSS periods from 4–6μm to 15–25μm.We report a maximal period of 25μm,which is the largest period ever reported for SWPSS,~10 and~4 times the maximal periods(2.4μm/6.5μm)of SWPSS ever achieved by fs and ns laser ablation,respectively.The formation of triangular and rhombic LIPSS does not depend on the laser(power)or processing(scan interval and scan methodology)parameters but strongly depends on the material composition and is unachievable on other metals,such as Sn,Al,Ti,Zn,and Zr.This paper proposes and discusses possible mechanisms for molten droplet generation/spread/solidification,Marangoni convection flow for SWPSS formation,and linear-to-circular polarization transition for triangular and rhombic LIPSS formation.Reflectance and iridescence of as-prepared SWPSS and LIPSS are characterized.It was found that besides insufficient ablation on W,the iridescence density of Ta-,Mo-,Nb-LIPSS follows the sequence of melting temperatures:Ta>Mo>Nb,which indicates that the melting temperature of metals may affect the regularity of LIPSS.This work may inspire significant interest in further enriching the diversity of LIPSS and SWPSS.展开更多
·AIM: To compare the effect of suction on the macular thickness and retinal nerve fiber layer(RNFL) thickness during laser in situ keratomileusis(LASIK) used Ziemer FEMTO LDV femtosecond laser(Ziemer group) and M...·AIM: To compare the effect of suction on the macular thickness and retinal nerve fiber layer(RNFL) thickness during laser in situ keratomileusis(LASIK) used Ziemer FEMTO LDV femtosecond laser(Ziemer group) and Moria M2 automated microkeratome(Moria group) for flap creation.· METHODS: Fourier-domain optical coherence tomography(FD-OCT) was used to measure macular thickness, ganglion cell complex thickness and RNFL thickness of 204 eyes of 102 patients with the Ziemer femtosecond laser(102 eyes) and the Moria M2microkeratome(102 eyes) before surgery and 30min; 1,3d; 1wk; 1, 3mo; 1y after surgery.· RESULTS: The average foveal thickness and parafoveal retinal thickness 30 min after the surgery were statistically more than that before surgery(Ziemer P 【0.001,P =0.003 and Moria P=0.001, P=0.006) and the effect was less in the Ziemer group than that in the Moria group(P all 【0.05). The ganglion cell complex thickness was not significantly changed in both groups(P all 】0.05). The RNFL thickness was statistically less 30 min after surgery in both groups(P=0.014, P 【0.001), but the influence was less in Ziemer group than that in Moria group(P =0.038).However, the RNFL thickness had recovered to the preoperative level only 1d after surgery.·CONCLUSION: The suction of femtosecond laser and mechanical microkeratome led to the increase in macular central fovea thickness and the decrease in RNFL thickness values at the early stage after LASIK. The effect of suction on macular and the RNFL thicknesses in Ziemer group is smaller than that in Moria group.展开更多
基金supported by the USTC Research Funds of the Double First-Class Initiative(Nos.YD2090002013,YD234000009)the National Natural Science Foundation of China(Nos.61927814,62325507,52122511,U20A20290,62005262)。
文摘The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic surface.The electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic force.Positively or negatively charged droplets can also be driven by TET based on electrostatic attraction and repulsion.TET enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(e.g.ethanol with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed system.Various droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0307701)the National Natural Science Foundation of China(Grant Nos.11674128,11674124,and 11974138).
文摘We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures,and predict the changes of ablation morphology and lattice temperature.For investigating the effect of sample temperature on femtosecond laser processing,we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model.The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises.When the sample temperature rises from 300 K to 600 K,the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation,and the ablation depth increases by 20%.The simulated ablation depths follow the same general trend as the experimental values.This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.
基金supported by the National Natural Science Foundation of China(52275463,51772240)the National Key Research and Development Program of China(2021YFB3302000)the Key Research and Development Projects of Shaanxi Province,China(2018ZDXM-GY-135)。
文摘The development of energy storage devices with high energy density relies heavily on thick film electrodes,but it is challenging due to the limited ion transport kinetics inherent in thick electrodes.Here,we report on the preparation of a directional vertical array of micro-porous transport networks on LTO electrodes using a femtosecond laser processing strategy,enabling directional ion rapid transport and achieving good electrochemical performance in thick film electrodes.Various three-dimensional(3D)vertically aligned micro-pore networks are innovatively designed,and the structure,kinetics characteristics,and electrochemical performance of the prepared ion transport channels are analyzed and discussed by multiple characterization and testing methods.Furthermore,the rational mechanisms of electrode performance improvement are studied experimentally and simulated from two aspects of structural mechanics and transmission kinetics.The ion diffusion coefficient,rate performance at 60 C,and electrode interface area of the laser-optimized 60-15%micro-porous transport network electrodes increase by 25.2 times,2.2 times,and 2.15 times,respectively than those of untreated electrodes.Therefore,the preparation of 3D micro-porous transport networks by femtosecond laser on ultra-thick electrodes is a feasible way to develop high-energy batteries.In addition,the unique micro-porous transport network structure can be widely extended to design and explore other high-performance energy materials.
基金supported by the National Natural Science Foundation of China(Nos.52122511,61927814,and U20A20290)Anhui Provincial Natural Science Foundation(2308085QF218)+5 种基金China National Postdoctoral Program for Innovative Talents(BX20230351)China Postdoctoral Science Foundation(2023M733382)National Key R&D Program of China(2021YFF0502700)Major Scientific and Technological Projects in Anhui Province(202203a05020014)Fundamental Research Funds for the Central Universities(WK5290000003 and WK2090000058)Youth Innovation Promotion Association CAS(Y2021118)。
文摘Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness.Despite research efforts,challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance.To address these challenges,we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method.Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber(1.03 kPa),our actuator exhibits an excellent deformation angle(265.25?)and actuation bending angular velocity(284.66 rad·s^(-1)).Furthermore,multiple actuators have been combined to build an artificial gripper with a wide range of functionalities.Our actuator presents new possibilities for designing small-scaleartificial machines and supports advancements in ultrafast soft and miniaturized robotics.
文摘Objective:To evaluate the clinical effect of full femtosecond laser surgery in the treatment of myopia patients.Methods:120 myopia patients admitted to our hospital from January 2022 to June 2023 were selected.According to the random number table method,60 patients in the observation group underwent full femtosecond laser surgery,and 60 patients in the control group underwent femtosecond laser-assisted in situ keratomileusis(FS-LASIK)surgery.The clinical effects of the two groups were compared.Results:10 days postoperatively and 6 months after operation,the visual acuity level of the observation group was higher than that of the control group,the postoperative corneal asphericity coefficient and corneal full-thickness were lower than those of the control group,and the total effective rate 6 months after operation was higher than that of the control group(P<0.05).Conclusion:Full femtosecond laser surgical treatment can improve the postoperative visual acuity of patients with myopia,enhance the corneal asphericity coefficient(Q)and corneal full-thickness,and exert significant clinical effects.
基金This work is supported by Academic Research Fund Tier 2,Ministry of Education-Singapore(MOE2019-T2-2-147)T.C.acknowledges support from the National Key Research and Development Program of China(2019YFA0709100,2020YFA0714504).
文摘Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere femtosecond laser irradi-ation in far field.By varying laser fluence and scanning speed,nano-feature sizes can be flexibly tuned.Such small patterns are attributed to the co-effect of microsphere focusing,two-photons absorption,top threshold effect,and high-repetition-rate femtosecond laser-induced incubation effect.The minimum feature size can be reduced down to~30 nm(λ/26)by manipulating film thickness.The fitting analysis between the ablation width and depth predicts that the feature size can be down to~15 nm at the film thickness of~10 nm.A nano-grating is fabricated,which demonstrates desirable beam diffraction performance.This nano-scale resolution would be highly attractive for next-generation laser nano-lithography in far field and in ambient air.
文摘We report novel results on top-down percussion drilling in different glasses with femtosecond laser GHz-bursts.Thanks to this particular regime of light–matter interaction,combining non-linear absorption and thermal cumulative effects,we obtained crack-free holes of aspect ratios exceeding 30 in sodalime and 70 in fused silica.The results are discussed in terms of inner wall morphology,aspect ratio and drilling speed.
基金Supported by the Natural Science Foundation of Guangdong Province,China(No.2022A1515010742)Hunan Provincial Natural Science Foundation of China(No.2021JJ30045)the Science Research Grant of Aier Eye Hospital Group(No.AF2102D5,No.AF2201D06,No.AF2201D05).
文摘AIM:To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laserassisted phacoemulsification(FLACS).METHODS:This study enrolled patients with cataract combined with regular corneal astigmatism of>0.75 D,who underwent FLACS.Symmetrical arc incision was set at 8 mm diameter and 85%depth.The follow-up time was 3-24mo(4.92±3.49mo).Pentacam recorded the corneal astigmatism and higher-order aberration at pre-operation and post-operation.The changes in corneal astigmatism were analyzed by Alpins method.The correlation of astigmatism type,age,corneal horizontal diameter,corneal thickness,arc incision length,and correction index(CI)was analyzed,and the residual corneal astigmatism was compared with the residual whole eye astigmatism.RESULTS:Totally 79 patients(102 eyes)were enrolled,10 patients had corneal epithelial injury,1 patient occurred corneal epithelial hyperplasia.The corneal astigmatism was 1.23±0.38 D pre-operation,and decreased to 0.76±0.39 D post-operation(t=10.146,P=0.000).Corneal high-order aberration was 0.17±0.08μm pre-operation and 0.24±0.11μm post-operation(t=-5.186,P=0.000).The residual corneal astigmatism and residual whole eye astigmatism were no significant difference(t=-0.347,P=0.729).Using Alpin’s method,the following were determined:target-induced astigmatism(TIA)=1.23±0.38 D,surgeryinduced astigmatism(SIA)=0.77±0.45 D,difference vector(DV)=0.77±0.39 D,and CI=0.54±0.28.Age,astigmatism size,corneal horizontal diameter,corneal thickness,and arc incision length were not correlated with CI.The CI for against the rule astigmatism(ATR)was better than that for with the rule astigmatism(WTR;P=0.001).CONCLUSION:Femtosecond laser-assisted astigmatic keratotomy has better CI of ATR,but increase higher-order corneal aberration.CI is not ideal,it’s not a perfect choice if we pursue ideal correction effect.
基金We are grateful for financial supports from the Ministry of Science and Technology of China(Grant No.2021YFA1401100)National Natural Science Foundation of China(Grant Nos.12074123,11804227,91950112),and the Foundation of‘Manufacturing beyond limits’of Shanghai.
文摘This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LIPSSs exhibited good properties as nanowires,with a resistivity almost equal to that of the initial ITO film.By changing the laser fluence,the nanowire resistances could be tuned from 15 to 73 kΩ/mm with a consistency of±10%.Furthermore,the average transmittance of the ITO films with regular LIPSSs in the range of 1200-2000 nm was improved from 21%to 60%.The regular LIPSS is promising for transparent electrodes of nano-optoelectronic devices-particularly in the near-infrared band.
基金supported by the National Natural Science Foundation of China (Nos. 52122511, 52105492, and 62005262)the National Key Research and Development Program of China (No. 2021YFF0502700)+2 种基金the Students’ Innovation and Entrepreneurship Foundation of USTC (Nos. CY2022G32 and XY2022G02CY)the USTC Research Funds of the Double First-Class Initiative (No. YD2340002009)CAS Project for Young Scientists in Basic Research (No. YSBR-049)
文摘Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable properties and functions to address the demands of ever-changing application environments that are becoming more intricate.Among many fabrication methods for stimulus-responsive structures,femtosecond laser direct writing(FsLDW)has received increasing attention because of its high precision,simplicity,true three-dimensional machining ability,and wide applicability to almost all materials.This paper systematically outlines state-of-the-art research on stimulus-responsive structures prepared by FsLDW.Based on the introduction of femtosecond laser-matter interaction and mainstream FsLDW-based manufacturing strategies,different stimulating factors that can trigger structural responses of prepared intelligent structures,such as magnetic field,light,temperature,pH,and humidity,are emphatically summarized.Various applications of functional structures with stimuli-responsive dynamic behaviors fabricated by FsLDW,as well as the present obstacles and forthcoming development opportunities,are discussed.
文摘A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.
文摘The tunneling ionization (TI) is the most dominated ionization process in the production of terahertz radiation by two femtosecond lasers, although its validity above the ionization threshold of some gases is uncertain. In the present research, we employ a 1D fluid code to simulate the efficiency of the produced terahertz radiation by two femtosecond laser beams in air plasma. Two ionization models in the context of the TI process which are the Ammosov-Delone-Krainov (ADK) for noble gases and its developed molecular ADK (MO-ADK) model for molecular gases are intrinsically used to conduct this study. The main target of the present research is to examine the validity of these models Above-Threshold-Ionization (ATI) of these gases. For this purpose, we simulated the ionization rate and the power spectrum of the produced radiation, in addition we numerically evaluated the efficiency of the produced radiation as function of the input beams intensity at particular energy fraction factor, relative phase and initial pulse duration of these beams. These calculations conducted for a selected noble gas at varying energy levels and a chosen molecular air plasma gas at different quantum numbers. Numerical results near and above the ionization threshold of the selected gases have clarified that the ADK and MO-ADK model are successful valid to study the efficiency of the produced THz radiation at low energy levels and small quantum numbers of the selected gases, meanwhile, with any further increase in the energy level and the quantum number values of these gases, both of the ADK and MO-ADK are failed to correctly analyze the efficiency process and estimate its fundamental parameters.
文摘AIM: To compare and calculate the 3-year refractive results, higher-order aberrations (HOAs), contrast sensitivity (CS) and dry eye parameters after small incision lenticule extraction (SMILE) and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for correction of high myopia and myopic astigmatism. METHODS: In this prospective, non-randomized comparative study, 78 eyes with spherical equivalent (SE) of -8.11±1.09 diopters (D) received a SMILE surgery, and 65 eyes with SE of -8.05±1.12 D received a wavefront-guided FS-LASIK surgery with the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) for flap cutting. Visual acuity, manifest refraction, CS, HOAs, ocular surface disease index (OSDI) and tear break-up time (TBUT) were evaluated during a 3-year follow-up. RESULTS: The difference of uncorrected distance visual acuity (UDVA) postoperatively was achieved at lmo and at 3mo, whereas the difference of the mean UDVA between two groups at 3y were not statistically significant (t=-1.59, P=-0.13). The postoperative change of SE was 0.89 D in the FS-LASIK group (t=5.76, P=0.00), and 0.14 D in the SMILE group (t=-0.54, P=0.59) from lmo to 3y after surgery. At 3-year postoperatively, both HOAs and spherical aberrations in the SMILE group were obviously less than those in the FS-LASIK group (P=0.00), but the coma root mean square (RMS) was higher in the SMILE group (0.59±0.26) than in the FS-LASIK group (0.29±0.14, P=0.00). The mesopic CS values between two groups were not statistically significant at 3y postoperatively. Compared with the FS-LASIK group, lower OSDI scores and longer TBUT values were found in the SMILE group at Imo and 3mo postoperatively. With regard to safety, no eye lost any line of CDVA in both groups at 3y after surgery. CONCLUSION: Both SMILE and wavefront-guided FS- LASIK procedures provide good visual outcomes. Both procedures are effective and safe, but SMILE surgery achieve more stable long-term refractive outcome and better control of early postoperative dry eye as compared to FS-LASIK.
文摘Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty(LTK)in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery(FLACS).This is the first report of both procedures combined simultaneously,with or without history of LTK.Case Description:A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004,with subsequent surgically induced high corneal astigmatism,and with age-related nuclear cataract of both eyes.IOL master demonstrated+7.71 diopters of astigmatism at 163 degree right eye and+3.29 diopters of astigmatism at 4 degree left eye.After extensive discussion of the risks and benefits,the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions(RIs)and toric IOL(Alcon SN6AT9)right eye;FLACS with toric IOL(Alcon SN6AT7)alone left eye.At 2-year follow-up,uncorrected visual acuity was 20/30 right eye,20/25 left eye.His best corrected visual acuity was 20/25(+0.25+1.00 axis 21)right eye and 20/20(plano+0.25 axis 90)left eye;his best corrected near visual acuity was J1+with add+2.50 diopters right eye and left eye.Conclusions:Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery.An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9,in our case,simultaneously,which can achieve an excellent long term visual outcome.
文摘AIM: To compare the complication rate of femtosecond laser-assisted cataract surgery(FLACS) and traditional phacoemulsification for the first 18 mo of FLACS use at a private surgical center in Hawaii.METHODS: A retrospective chart review was conducted from January 2012 to June 2013. The first 273 consecutive eyes receiving FLACS and 553 eyes receiving traditional phacoemulsification were examined.All surgeries were performed at a single surgical center in Hawaii. The presence of intraoperative complications was used as the main outcome measure. Approval was obtained from the institutional review board of the University of Hawaii.RESULTS: The overall complication rate for FLACS was 1.8%, while that of the traditional procedure was5.8%(P 【0.05). A majority of the surgeons(80%) had a lower complication rate while using FLACS.CONCLUSION: FLACS is comparable in safety, if not safer, than traditional cataract surgery when performed by qualified cataract surgeons on carefully selected patients.
文摘AIM:To evaluate the possible differences in visual quality between small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(FS-LASIK)for myopia.METHODS:A Meta-analysis was performed.Patients were from previously reported comparative studies treated with SMILE versus FS-LASIK.The Pub Med,EMBASE,Cochrane,Web of Science and Chinese databases(i.e.WANFANG and CNKI)were searched in Nov.of 2016 using Rev Man 5.1 version software.The differences in visual acuity,aberration and biomechanical effects within six months postoperatively were showed.Twenty-seven studies including 4223 eyes were included.RESULTS:No significant differences were observed between SMILE and FS-LASIK in terms of the proportion of eyes that lost one or more lines of corrected distance visual acuity after surgery(P=0.14),the proportion of eyes achieving an uncorrected distance visual acuity of 20/20or better(P=0.43),the final refractive spherical equivalent(P=0.89),the refractive spherical equivalent within±1.00diopter of the target values(P=0.80),vertical coma(P=0.45)and horizontal coma(P=0.06).Compared with the FSLASIK group,total higher-order aberration(P〈0.001)and spherical aberration(P〈0.001)were higher and the decrease in corneal hysteresis(P=0.0005)and corneal resistance factor(P=0.02)were lower in the SMILE group.CONCLUSION:SMILE and FS-LASIK are comparable in efficacy,safety and predictability for correcting myopia.However,the aberration in the SMILE group is superior to that in the FS-LASIK group,and the loss of biomechanical effects may occur less frequently after SMILE than after FS-LASIK.
基金Supported by National Natural Science Foundation of China (No.81070754)
文摘AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intendedfiap thickness was 110 mu m and 160 mu m respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45 degrees and 135 degrees meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43 +/- 4.70 mu m, while 125.90 +/- 17.50 mu m in the Hansatome group. The difference between the actual and the expectedfiap thickness was 5.61 +/- 3.84 mu m and 31.52 +/- 12.27 mu m, respectively. The Hansatome group had presented a statistically significant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.
文摘AIM: To compare the outcomes of laser in situ keratomileusis (LASIK) performed with a femtosecond laser (Femtec, Technolas Perfect Vision GmbH, Germany) versus a mechanical microkeratome (Hansatome, Bausch and Lomb, USA) for the correction of myopia and astigmatism. ·METHODS: In this retrospective study, patients who had undergone LASIK using the 80 -kHz Femtec femtosecond laser were compared to age- and refraction- matched patients in whom the Hansatome microkeratome was used. Refractive and visual results 1 month and 3 months postoperatively, and complication rates were compared between the two groups. ·RESULTS: A total of 280 eyes were analyzed (140 in each group). At 3 months postoperatively in the Femtec vs Hansatome group, spherical equivalent refraction was within ±1.00D of emmetropia in 140 vs 138 eyes (P = 0.498), the cylinder was within ±0.50D in 137 vs 139 eyes (P =0.622), and the UDVA was 20/20 or better in 136 vs 137 eyes (P =0.724), respectively. There was no statistically significant difference in the complication rates between the two groups (P =0.099). ·CONCLUSION: LASIK performed both with Femtec femtosecond laser and Hansatome microkeratome achieved satisfactory refractive and visual results at 3 months postoperatively, without significant differences in efficacy, safety, and complication rates between the two procedures.
文摘Currently,supra-wavelength periodic surface structures(SWPSS)are only achievable on silica dielectrics and silicon by femtosecond(fs)laser ablation,while triangular and rhombic laser induced periodic surface structures(LIPSS)are achievable by circularly polarized or linear cross-polarized femtosecond laser.This is the first work to demonstrate the possibility of generating SWPSS on Sn and triangular and rhombic LIPSS on W,Mo,Ta,and Nb using a single linearly polarized femtosecond laser.We discovered,for the first time,SWPSS patches with each possessing its own orientation,which are completely independent of the light polarization direction,thus,breaking the traditional rules.Increasing the laser power enlarges SWPSS periods from 4–6μm to 15–25μm.We report a maximal period of 25μm,which is the largest period ever reported for SWPSS,~10 and~4 times the maximal periods(2.4μm/6.5μm)of SWPSS ever achieved by fs and ns laser ablation,respectively.The formation of triangular and rhombic LIPSS does not depend on the laser(power)or processing(scan interval and scan methodology)parameters but strongly depends on the material composition and is unachievable on other metals,such as Sn,Al,Ti,Zn,and Zr.This paper proposes and discusses possible mechanisms for molten droplet generation/spread/solidification,Marangoni convection flow for SWPSS formation,and linear-to-circular polarization transition for triangular and rhombic LIPSS formation.Reflectance and iridescence of as-prepared SWPSS and LIPSS are characterized.It was found that besides insufficient ablation on W,the iridescence density of Ta-,Mo-,Nb-LIPSS follows the sequence of melting temperatures:Ta>Mo>Nb,which indicates that the melting temperature of metals may affect the regularity of LIPSS.This work may inspire significant interest in further enriching the diversity of LIPSS and SWPSS.
文摘·AIM: To compare the effect of suction on the macular thickness and retinal nerve fiber layer(RNFL) thickness during laser in situ keratomileusis(LASIK) used Ziemer FEMTO LDV femtosecond laser(Ziemer group) and Moria M2 automated microkeratome(Moria group) for flap creation.· METHODS: Fourier-domain optical coherence tomography(FD-OCT) was used to measure macular thickness, ganglion cell complex thickness and RNFL thickness of 204 eyes of 102 patients with the Ziemer femtosecond laser(102 eyes) and the Moria M2microkeratome(102 eyes) before surgery and 30min; 1,3d; 1wk; 1, 3mo; 1y after surgery.· RESULTS: The average foveal thickness and parafoveal retinal thickness 30 min after the surgery were statistically more than that before surgery(Ziemer P 【0.001,P =0.003 and Moria P=0.001, P=0.006) and the effect was less in the Ziemer group than that in the Moria group(P all 【0.05). The ganglion cell complex thickness was not significantly changed in both groups(P all 】0.05). The RNFL thickness was statistically less 30 min after surgery in both groups(P=0.014, P 【0.001), but the influence was less in Ziemer group than that in Moria group(P =0.038).However, the RNFL thickness had recovered to the preoperative level only 1d after surgery.·CONCLUSION: The suction of femtosecond laser and mechanical microkeratome led to the increase in macular central fovea thickness and the decrease in RNFL thickness values at the early stage after LASIK. The effect of suction on macular and the RNFL thicknesses in Ziemer group is smaller than that in Moria group.