Thulium fiber laser lithotripsy:Is it living up to the hype?

Objective:The holmium:yttrium-aluminium-garnet laser(Ho:YAG)has been the gold standard for laser lithotripsy over the last three decades.After demonstrating good in vitro efficacy,the thulium fiber laser(TFL)has been recently released in the market and the initial clinical results are encouraging.This article aims to review the main technology differences between the Ho:YAG laser and the TFL,discuss the initial clinical results with the TFL as well as the optimal settings for TFL lithotripsy.Methods:We reviewed the literature focusing on the technological aspects of the Ho:YAG laser and TFL as well as the results of in vitro and in vivo studies comparing both technologies.Results:In vitro studies show a technical superiority of TFL compared to the Ho:YAG laser and encouraging results have been demonstrated in clinical practice.However,as TFL is a new technology,limited studies are currently available,and the optimal settings for lithotripsy are not yet established.Conclusion:TFL has the potential to be an alternative to the Ho:YAG laser,but more reports are still needed to determine the optimal laser for lithotripsy of urinary tract stones when considering all parameters including effectiveness,safety,and costs.

A method for reducing thermal injury during the ureteroscopic holmium laser lithotripsy

Objective:Many studies have demonstrated the heat effect from the holmium laser lithotripsy can cause persistent thermal injury to the ureter.The purpose of this study was to elucidate the use of a modified ureteral catheter with appropriate firing and irrigation to reduce the thermal injury to the“ureter”during the ureteroscopic holmium laser lithotripsy in vitro.Methods:An in vitro lithotripsy was performed using a modified catheter(5 Fr)as the entrance for the irrigation and the holmium laser fiber while using the remaining space in the ureteroscopic channel as an outlet.Different laser power settings(10 W,20 W,and 30 W)with various firing times(3 s,5 s,and 10 s)and rates of irrigation(15 mL/min,20 mL/min,and 30 mL/min)were applied in the experiment.Temperature changes in the“ureter”were recorded with a thermometer during and after the lithotripsy.Results:During the lithotripsy,the local highest mean temperature was 60.3℃ and the lowest mean temperature was 26.7℃.When the power was set to 10 w,the temperature was maintained below 43℃ regardless of laser firing time or irrigation flow.Regardless of the power or firing time selected,the temperature was below 43℃ at the rate of 30 mL/min.There was a significant difference in temperature decrease when continuous 3 s drainage after continuous firing(3 s,5 s,or 10 s)compared to with not drainage(p<0.05)except for two conditions of 0.5 J×20 Hz,30 mL/min,firing 5 s,and 1.0 J×10 Hz,30 mL/min,firing 5 s.Conclusion:Our modified catheter with timely drainage reducing hot irrigation may significantly reduce the local thermal injury effect,especially along with the special interrupted-time firing setting during the simulated holmium laser procedure.

Bouveret syndrome masquerading as a gastric mass-unmasked with endoscopic luminal laser lithotripsy:A case report

BACKGROUND Bouveret syndrome,also known as gallstone ileus,is a rare form of gastric outlet obstruction accounting for 1%-3%of cases.This condition is most often reported in females.The diagnosis can be challenging and is often missed due to atypical presentations,which occasionally mimic gastric outlet obstruction symptoms such as nausea,vomiting,loss of appetite and hematemesis.The symptoms vary with stone size.Larger stones are managed with a surgical approach,but this carries increased morbidity and mortality.Over the past decade,the endoscopic approach has emerged as an alternative mode of treatment,but it is generally unsuccessful in the management of larger-sized stones.A literature review revealed cases of successful endoscopic treatment requiring multiple sessions for stone sizes measuring up to about 4.5 cm.Here we present a unique case of an elderly patient with Bouveret syndrome with a 5 cm stone mimicking a gastric mass and causing gastric outlet obstruction,who was successfully managed in a single session using a complete endoscopic approach with laser lithotripsy.CASE SUMMARY An 85-year-old female patient presented with 1-month history of intermittent abdominal pain,vomiting,decreased appetite and weight loss.An abdominal computed tomography showed a 4.5 cm×4.7 cm partially calcified mass at the gastric pylorus causing gastric outlet obstruction.Endoscopy showed an ulcerated fistulous opening and a large 5 cm impacted gallstone in the duodenal bulb.Endoscopic nets and baskets were used in an attempt to remove the stone,but this approach was unsuccessful.Given her advanced age,poor physical condition and underlying comorbidities,she was deemed to be high-risk for surgery.Thus,a minimally invasive approach using endoscopic laser lithotripsy was attempted and successfully treated the stone.Post-procedure,the patient experienced complete resolution of her symptoms with no complications and was able to tolerate her diet.She was subsequently discharged home at 48 h,with an uneventful recovery.CONCLUSION In our paper we describe Bouveret syndrome and highlight its management with a novel endoscopic approach of laser lithotripsy in addition to various other endoscopic approaches available to date and its success rates.

Management hepatolithiasis with operative choledochoscopic FREDDY laser lithotripsy combined with or without hepatectomy

BACKGROUND: Hepatolithiasis is very common in East Asia. It is benign in nature, but has a high recurrence rate. It is likely to lead to biliary cirrhosis and increase the risk of cholangiocarcinoma. Hence, the treatment of hepatolithiasis is difficult but vital. In this report, we present a novel approach to manage hepatolithiasis using the choledochoscopic Frequency-Doubled Double pulse Nd:YAG (FREDDY) laser lithotripsy combined with or without hepatectomy. METHODS: Between July 2009 and October 2012, 45 patients underwent choledochoscopic FREDDY laser lithotripsy combined with or without hepatectomy (laser lithotripsy group). Fortyeight patients underwent a traditional operation (traditional method group) from January 2009 to June 2009. Comparative analysis was made of demographic and clinical characteristics of the two groups. RESULTS: The final stone clearance rate of the laser lithotripsy group was 93.3%, whereas that of the traditional method group was 85.4% (P=0.22). In the laser lithotripsy group, 2 patients experienced hemobilia and 3 patients had acute cholangitis. In the traditional method group, 3 patients had intraoperative hemorrhage, 1 patient had bile leakage, 6 patients had acute cholangitis, and 1 patient died of liver failure. Moreover, the operative time in the traditional method group was significantly longer than that in the laser lithotripsy group (P=0.01). The mean hospital stay of the patients in the traditional method group was longer than that in the laser lithotripsy group (9.8 vs8.2 days, P=0.17). Recurrent intrahepatic bile duct stones were not found during the follow-up period in the two groups. CONCLUSION: Operative choledochoscopic FREDDY laser lithotripsy combined with or without hepatectomy may be an effective and safe treatment for hepatolithiasis.

Ureteroscopic Holmium:YAG Laser Lithotripsy for Managing Ureteral Calculi (A Report of 168 Cases)

Summary: The effectiveness and safety of ureteroscopic holmium:YAG laser lithotripsy for managing ureteral calculi was evaluated. Ureteroscopic holmium:YAG laser lithotripsy was performed in 168 ureteral calculi (upper 27 cases, middle 33 cases and lower 108 cases). The results showed that the stone-free rate was 92.6 % in the upper ureteral calculi, 93.9 % in the middle ureteral calculi and 94.4 % in the lower ureteral calculi, respectively. The complication rate was 4.8 % (8 cases). It was suggested that ureteroscopic holmium:YAG laser lithotripsy is a highly effective and safe treatment modality for managing ureteral calculi.

Successful endoscopic treatment of a large impacted gallstone in the duodenum using laser lithotripsy,Bouveret’s syndrome:A case report

BACKGROUND Bouveret´s syndrome is defined as a gastric outlet obstruction after passage of a gallstone through a fistula into the duodenum.Due to its rarity,the diagnosis of Bouveret’s syndrome is often delayed and causes a high morbidity and mortality rate.CASE SUMMARY A 93-year-old female presented with worsening pain in the right upper abdomen and vomiting.A gastroscopy revealed fluid retention caused by a massive obstructive stone in the bulbus.Endoscopic laser lithotripsy of the impacted stone was planned after multidisciplinary consultation.A Dornier Medilas H Solvo lithotripsy 350μm laser fiber(10 Hz,2 Joules)was used to disintegrate the stone into smaller pieces.The patient recovered completely.CONCLUSION A mechanical obstruction due to a gallstone that has entered the gastrointestinal tract is a complication that appears in 0.3%-0.5%of patients who have cholelithiasis.Stones larger than 2 cm can become impacted in the digestive tract,which occurs mostly in the terminal ileum.In approximately 1%-3%of cases,the stones cause obstruction in the duodenum.This phenomenon is called Bouveret’s syndrome.As this condition is mostly observed in elderly individuals with multiple comorbidities,treatment by an open surgical approach is unsuitable.Endoscopic removal is the preferred technique.The benefit of using laser lithotripsy is the precise targeting of energy onto the stone with minimal tissue injury.Endoscopic laser lithotripsy is a safe and feasible treatment option for Bouveret’s syndrome.

Ureteroscopic Management of Ureteral Calculi: Pneumatic versus Holmium: YAG Laser Lithotripsy

Background: Among various intracorporeal lithotripters, pneumatic lithotripter has become the widely used tool for the treatment of urinary stones. Recently the holmium: YAG laser has been used with a wide range of potential urological applications, including intracorporeal lithotripsy of urinary calculi. Purpose: Compare the effectiveness and complications of treatment for ureteric stones between holmium laser lithotripsy and pneumatic lithotripsy. Material and Methods: Comparison of 100 patients presented with ureteric stones, group one (50) of whom were treated with pneumatic lithotripsy and group two (50) with holmium laser was done and the effectiveness and complications of both were analyzed. Results: There was no difference in patient age, sex, stone size and location of stones between the two groups. The immediate stone free rates were 88% in the holmium: YAG group and 66% in the pneumatic lithotripsy group (p < 0.05). The four weeks stone free rates were 98% and 94% respectively (p = 0.07). The mean ± SD operative time in the holmium: YAG group (40 ± 26 min) was shorter than those with pneumatic lithotripsy group (60 ± 40 min). Postoperative stay in hospital was less than 24 hours in holmium: YAG group (70.4%) and shorter than those for pneumatic group (29.6%) (p < 0.002). Post treatment complications such as ureteral perforation were encountered in only two patients who underwent pneumatic lithotripsy. Other complications, such as mucosal injury, ureteral perforation and postoperative fever;there was no statistically significant difference between the two groups. While light hematuria was found more frequently in the pneumatic group (14%) in comparison to laser group (12%) (p = 0.02). On the other hand, the overall complication rates between the two groups was statistically significant (8%) laser group vs. (32%) pneumatic group (p = 0.003). Conclusions: Holmium: YAG laser lithotripsy was associated with shorter operation time and postoperative hospitalization period. These data suggest that holmium: YAG lithotripsy was safe and more effective than Pneumatic lithotripsy in the aspect of immediate stone free rate. We believe that holmium: YAG is an excellent treatment modality for managing ureteral calculi.

Systematic evaluation of a holmium:yttrium-aluminum-garnet laser lithotripsy device with variable pulse peak power and pulse duration

Objective:The Holmium:yttrium-aluminum-garnet(Ho:YAG)laser is the standard lithotrite for ureteroscopy.This paper is to evaluate a Ho:YAG laser with a novel effect function in vitro,which allows a real-time variation of pulse duration and pulse peak power.Methods:Two types of phantom calculi with four degrees of hardness were made for fragmentation and retropulsion experiments.Fragmentation was analysed at 5(0.5 J/10 Hz),10(1 J/10 Hz),and 20(2 J/10 Hz)W in non-floating phantom calculi,retropulsion in an ureteral model at 10(1 J/10 Hz)and 20(2 J/10 Hz)W using floating phantom calculi.The effect function was set to 25%,50%,75%,and 100%of the maximum possible effect function at each power setting.Primary outcomes:fragmentation(mm^3),the distance of retropulsion(cm);
5 measurements for each trial.Results:An increase of the effect feature(25%vs.100%),i.e.,an increase of pulse peak power and decrease of pulse duration,improved Ho:YAG laser fragmentation.This effect was remarkable in soft stone composition,while there was a trend for improved fragmentation with an increase of the effect feature in hard stone composition.Retropulsion increased with increasing effect function,independently of stone composition.The major limitations of the study are the use of artificial stones and the in vitro setup.Conclusion:Changes in pulse duration and pulse peak power may lead to improved stone fragmentation,most prominently in soft stones,but also lead to increased retropulsion.This new effect function may enhance Ho:YAG laser fragmentation when maximum power output is limited or retropulsion is excluded.

Mid-Infrared Pulsed Laser Lithotripsy with a Tunable Laser Using Difference-Frequency Generation

A novel technique of lithotripsy was investigated with a mid-infrared tunable pulsed laser using difference-frequency generation (DFG). Human gallstone samples obtained from 24 patients were analyzed with their infrared absorption spectra. It was found that the principal components of the gallstones were different for the different patients and that the gallstone samples used in this research could be classified into four groups, i.e., mixed stones, calcium bilirubinate stones, cholesterol stones, and calcium carbonate stones. In addition, some gallstone samples had different compositions within the single stone. The mid-infrared laser tunable within a wavelength range of 5.5 - 10 μm was irradiated to the cholesterol stones at two different wavelengths of 6.83 and 6.03 μm, where the cholesterol stones had relatively strong and weak absorption peaks, respectively. As the result, the cholesterol stones were more efficiently ablated at the wavelength of 6.83 μm with the strong absorption peak. Therefore, it is suggested that the gallstones could be efficiently ablated by tuning the wavelength of the laser to the strong absorption peak of the gallstones. The higher efficiency of the ablation using the characteristic absorption peaks should lead to the safer treatment without damage to the surrounding normal tissues. In order to identify the composition of the gallstones in the patients, endoscopic and spectroscopic diagnosis using the DFG laser and an optical fiber probe made with two hollow optical fibers and a diamond attenuation total reflection prism should be useful. The absorption spectrum of the gallstones in the patients could be measured by measuring the energy of the DFG laser transmitted through the optical fiber probe and by scanning the wavelength of the DFG laser.

Low-pressure pulse flushing choledochoscopy combined with neodymium laser lithotripsy for the treatment of intrahepatic bile duct stones

Cholelithiasis is a common and frequently occurring disease in East Asia.Intrahepatic bile duct stone is a benign disease,but the recurrence rate is high.The incidence of postoperative residual stones after traditional manual stone removal can be30%–96%^([1]).The emergence of endoscopes is therefore a milestone in the treatment of hepatolithiasis.Among the various approaches,choledochoscopy combined with laser lithotripsy has become the main procedure for intrahepatic bile duct stone removal^([2]).Lithotripsy alone has the disadvantages of low stoneremoving efficiency and blurred choledochoscope vision while performing the procedure.Currently,our team has achieved satisfactory results in the removal of intrahepatic bile duct stones with low-pressure pulse flushing and neodymium laser lithotripsy.

Role of Removing Stasis and Reducing Heat Formula in Clearance of Proximal Ureteral Calculi after Ureteroscopic Ho:YAG Laser Lithotripsy: A Prospective Randomized Study

Objective To prospectively evaluate the efficacy of Removing Stasis and Reducing Heat Formula in accelerating calculus clearance and improving lower urinary tract symptoms of patients with proximal ureteral calculi after ureteroscopic Ho:YAG laser lithotripsy. Methods A total of 138 patients with proximal ureteral calculi underwent ureteroscopic Ho:YAG laser lithotripsy by a single endocrinologist. Stone size varied from 10 to 15 mm. After operation, the patients were randomly divided into three groups: the control group(group A), tamsulosin group(group B), and Removing Stasis and Reducing Heat Formula group(group C). The treatment lasted for 4 weeks or until stone clearance. The primary and secondary outcomes of the three groups at follow-up were assessed. Results Of the 131 patients available for follow-up, 44 cases were in the group A, 45 in the group B, and 42 in the group C, respectively. The stone free rate at 2 weeks in the groups B and C were significantly higher than that in the group A(95.56%, 97.62% vs. 79.55%; all P<0.05). The ureteral colic rate and mean time of fragment expulsion were significantly reduced in the groups B(4.44% and 7.86±4.99 days) and C(2.43% and 6.76±4.37 days) compared with the group A(22.73% and 11.54±9.89 days, all P<0.05). On the day of double-J ureteric stent removal, the group C differed significantly from the group A in the total International Prostate Symptom Score, irritative subscore, obstructive subscore, and quality of life score(all P<0.05). Conclusion Removing Stasis and Reducing Heat Formula in the medical expulsive therapy might be an effective modality for patients with calculus in the proximal uretera after ureteroscopic Ho:YAG laser lithotripsy.

Flexible ureteroscopic treatment of kidney stones: How do the new laser systems change our concepts?

Objective: Flexible ureteroscopy (fURS) has become a widely accepted and effective technique for treating kidney stones. With the development of new laser systems, the fURS approach has evolved significantly. This literature review aims to examine the current state of knowledge on fURS treatment of kidney stones, with a particular focus on the impact of the latest laser technologies on clinical outcomes and patient safety.Methods: We conducted a search of the PubMed/PMC, Web of Science Core Collection, Scopus, Embase (Ovid), and Cochrane Databases for all randomized controlled trial articles on laser lithotripsy in September 2023 without time restriction.Results: We found a total of 22 relevant pieces of literature. Holmium laser has been used for intracavitary laser lithotripsy for nearly 30 years and has become the golden standard for the treatment of urinary stones. However, the existing holmium laser cannot completely powder the stone, and the retropulsion of the stone after the laser emission and the thermal damage to the tissue have caused many problems for clinicians. The introduction of thulium fiber laser and Moses technology brings highly efficient dusting lithotripsy effect through laser innovation, limiting pulse energy and broadening pulse frequency.Conclusion: While the holmium:yttrium-aluminum-garnet laser remains the primary choice for endoscopic laser lithotripsy, recent technological advancements hint at a potential new gold standard. Parameter range, retropulsion effect, laser fiber adaptability, and overall system performance demand comprehensive attention. The ablation efficacy of high-pulse-frequency devices relies on precise targeting, which may pose practical challenges.

Wavelength-interval switchable Brillouin–Raman random fiber laser through Brillouin pump manipulation

A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity configuration, featuring multiwavelength output with wavelength interval of double Brillouin frequency shifts. Through simultaneously injecting the BP light and its first-order stimulated Brillouin-scattered light into the cavity, the laser output exhibits a wavelength interval of single Brillouin frequency shift. The wavelength-interval switching effect can be manipulated by controlling the power of the first-order stimulated Brillouin scattering light. The experimental results show the multiwavelength output can be switched between double Brillouin frequency shift multiwavelength emission with a broad bandwidth of approximately 60 nm and single Brillouin frequency shift multiwavelength emission of 44 nm. The flexible optically controlled random fiber laser with switchable wavelength interval makes it useful for a wide range of applications and holds significant potential in the field of wavelength-division multiplexing optical communication.

Underwater four-quadrant dual-beam circumferential scanning laser fuze using nonlinear adaptive backscatter filter based on pauseable SAF-LMS algorithm

The phenomenon of a target echo peak overlapping with the backscattered echo peak significantly undermines the detection range and precision of underwater laser fuzes.To overcome this issue,we propose a four-quadrant dual-beam circumferential scanning laser fuze to distinguish various interference signals and provide more real-time data for the backscatter filtering algorithm.This enhances the algorithm loading capability of the fuze.In order to address the problem of insufficient filtering capacity in existing linear backscatter filtering algorithms,we develop a nonlinear backscattering adaptive filter based on the spline adaptive filter least mean square(SAF-LMS)algorithm.We also designed an algorithm pause module to retain the original trend of the target echo peak,improving the time discrimination accuracy and anti-interference capability of the fuze.Finally,experiments are conducted with varying signal-to-noise ratios of the original underwater target echo signals.The experimental results show that the average signal-to-noise ratio before and after filtering can be improved by more than31 d B,with an increase of up to 76%in extreme detection distance.

Recent developments in selective laser processes for wearable devices

Recently,the increasing interest in wearable technology for personal healthcare and smart virtual/augmented reality applications has led to the development of facile fabrication methods.Lasers have long been used to develop original solutions to such challenging technological problems due to their remote,sterile,rapid,and site-selective processing of materials.In this review,recent developments in relevant laser processes are summarized under two separate categories.First,transformative approaches,such as for laser-induced graphene,are introduced.In addition to design optimization and the alteration of a native substrate,the latest advances under a transformative approach now enable more complex material compositions and multilayer device configurations through the simultaneous transformation of heterogeneous precursors,or the sequential addition of functional layers coupled with other electronic elements.In addition,the more conventional laser techniques,such as ablation,sintering,and synthesis,can still be used to enhance the functionality of an entire system through the expansion of applicable materials and the adoption of new mechanisms.Later,various wearable device components developed through the corresponding laser processes are discussed,with an emphasis on chemical/physical sensors and energy devices.In addition,special attention is given to applications that use multiple laser sources or processes,which lay the foundation for the all-laser fabrication of wearable devices.

Vulnerability assessment of UAV engine to laser based on improved shotline method

Laser anti-drone technology is entering the sequence of actual combat,and it is necessary to consider the vulnerability of typical functional parts of UAVs.Since the concept of"vulnerability"was proposed,a variety of analysis programs for battlefield targets to traditional weapons have been developed,but a comprehensive assessment methodology for targets'vulnerability to laser is still missing.Based on the shotline method,this paper proposes a method that equates laser beam to shotline array,an efficient vulnerability analysis program of target to laser is established by this method,and the program includes the circuit board and the wire into the vulnerability analysis category,which improves the precision of the vulnerability analysis.Taking the UAV engine part as the target of vulnerability analysis,combine with the"life-death unit method"to calculate the laser penetration rate of various materials of the UAV,and the influence of laser weapon system parameters and striking orientation on the killing probability is quantified after introducing the penetration rate into the vulnerability analysis program.The quantitative analysis method proposed in this paper has certain general expansibility,which can provide a fresh idea for the vulnerability analysis of other targets to laser.

Effect of Different Laser Energy Nitriding on the Fretting Wear Performance of Zr Alloy

The zirconium(Zr)alloy fuel cladding is one of the key structural components of a nuclear reactor and the first and most important line of defense for accommodating fission products.During the operation of nuclear reactors,Zr alloy fuel cladding is subjected to extreme harsh environments,such as high temperature,high pressure and high flow rate for a long period of time.The wear and corrosion resistance of Zr alloys is important for the safe operation of nuclear reactors.Surface modification can effectively improve the corrosion and wear resistance of fuel cladding.Compared with coating technology,nitriding technology does not have problems for bonding between the coating and the substrate.Current research on surface nitriding of Zr alloys mainly focuses on plasma nitriding and ion implantation techniques.Research on laser nitriding of Zr alloy surfaces and their fretting wear characteristics is scarce.In this study,the surface of Zr alloy was treated with laser nitriding at different laser energies.The microstructure of Zr alloy treated with different laser energies and its fretting wear performance were studied.The results showed that after nitriding with different laser energies,the surface of the Zr alloy showed a typical molten state after melting,vaporizing and cooling under the thermal effect of the laser,and this state was more obvious with the increase of the laser energy.At the same time,doping of N atoms and formation of the ZrN phase led to different cooling rates in the molten zone that produced large tensile stresses after cooling.This led to cracks on the surface of Zr alloys after laser nitriding at different energies,and the crack density increased with increasing laser energy.This also led to an increase in the surface roughness of the Zr alloy with increasing laser energy after laser nitriding treatment.Due to the presence of water in the industrial nitrogen,nitrides were generated on the surface of the sample along with some oxides.When the laser energy was 100 mJ,there was no ZrN generation,and N existed mainly as a diffusion layer within the Zr alloy substrate.ZrN generated when the laser energy reached 200 mJ and above,which increased with the increase of laser energy.Due to the generation of ZrN phase and the presence of some oxides,the surface Vickers hardness of Zr alloys after laser nitriding treatment at different energies increased by 37.5%compared to Zr alloys.After laser nitriding treatment,the wear mechanism of Zr alloys changed.For the untreated Zr alloys,the wear mechanism was dominated by delamination and spalling wear,accompanied by oxidative and abrasive wear.The phenomenon of delamination and peeling decreased with the increase of laser energy.Wear mechanisms changed to predominantly abrasive wear with oxidative wear and delamination spalling.The wear volume of sample nitriding with laser energy 400 mJ was reduced by 46.5%compared with that of untreated Zr alloy.

Memristive feature and mechanism induced by laser-doping in defect-free 2D semiconductor materials

Memristors as non-volatile memory devices have gained numerous attentions owing to their advantages in storage,in-memory computing, synaptic applications, etc. In recent years, two-dimensional(2D) materials with moderate defects have been discovered to exist memristive feature. However, it is very difficult to obtain moderate defect degree in 2D materials, and studied on modulation means and mechanism becomes urgent and essential. In this work, we realized memristive feature with a bipolar switching and a configurable on/off ratio in a two-terminal MoS_(2) device(on/off ratio ~100), for the first time, from absent to present using laser-modulation to few-layer defect-free MoS_(2)(about 10 layers), and its retention time in both high resistance state and low resistance state can reach 2×10^(4) s. The mechanism of the laser-induced memristive feature has been cleared by dynamic Monte Carlo simulations and first-principles calculations. Furthermore, we verified the universality of the laser-modulation by investigating other 2D materials of TMDs. Our work will open a route to modulate and optimize the performance of 2D semiconductor memristive devices.

Internal phase control of fiber laser array based on photodetector array

Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback structure should be established to realize phase-locking. In this paper, an innovative internal active phase control CBC fiber laser array based on photodetector array is proposed. The dynamic phase noises of the laser amplifiers are compensated before being emitted into free space. And the static phase difference compensation of emitting laser array is realized by interference measurement based on photodetector array. The principle of the technique is illustrated and corresponding simulations are carried out, and a CBC system with four laser channels is built to verify the technique. When the phase controllers are turned on, the phase deviation of the laser array is less than λ/20, and ~ 95% fringe contrast of the irradiation distribution is obtained. The technique proposed in this paper could provide a reference for the system design of a massive high-power CBC system.

Femtosecond laser fabrication of 3D vertically aligned micro-pore network on thick-film Li_(4)Ti_(5)O_(12)electrode for high-performance lithium storage

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.