A high-performance LED-side-pumped two-rod Nd,Ce:YAG laser with continuous-wave(CW) and acousto–optical(A-O) Q-switched operation is demonstrated in this work. A symmetrically shaped flat–flat cavity with two identi...A high-performance LED-side-pumped two-rod Nd,Ce:YAG laser with continuous-wave(CW) and acousto–optical(A-O) Q-switched operation is demonstrated in this work. A symmetrically shaped flat–flat cavity with two identical LEDside-pumped laser modules is employed for power scalability. In the CW regime, the maximum output average power of laser at 1064 nm is 4.41 W, corresponding to a maximum optical conversion efficiency of 5.3% and a slope efficiency is 12.4%. In the active Q-switched regime, the pulse energy of laser reaches as high as 0.89 m J at a repetition rate of 800 Hz with a pulse width of 457.2 ns, the corresponding highest peak output power is 1.94 k W and the M~2 factor is measured to be about 8.8. To the best of the authors' knowledge, this is the first demonstration and the highest performance of a CW LED-side-pumped two-rod laser Nd,Ce:YAG with Watt-level output reported so far.展开更多
A diode-end-pumped Q-switched high-efficiency Nd, Cr:YAG laser with simultaneous dual-wavelength emission at 946nm and 1.3μm is demonstrated. The maximum output power of 1.93 W with simultaneous dual-wavelength oper...A diode-end-pumped Q-switched high-efficiency Nd, Cr:YAG laser with simultaneous dual-wavelength emission at 946nm and 1.3μm is demonstrated. The maximum output power of 1.93 W with simultaneous dual-wavelength operation is achieved at an absorbed pump power of 13.32 W and an absorbed slope efficiency of 15.15%. The maximum optical-optical efficiency is 14.49% with pulse widths of 16.38ns at 946nm and 26.65ns at 1.3μm. A maximum total repetition rate of 43.25 kHz is obtained.展开更多
A high-power passively Q-switched Nd:YAG laser operating at lll2nm with Cr4+:yAO as a saturable absorber is demonstrated. Under 808 nm diode-direct pumping, the maximum average output power of 2.73 W is achieved at...A high-power passively Q-switched Nd:YAG laser operating at lll2nm with Cr4+:yAO as a saturable absorber is demonstrated. Under 808 nm diode-direct pumping, the maximum average output power of 2.73 W is achieved at the pump power of 16.65 W, corresponding to an optical-to-optical conversion efficiency of 16.4%. At the same time, the pulse width, pulse repetition rate, single pulse energy and peak power are 27.2ns, 9 kHz, 303.3#3 and 11.2kW, respectively. As far as we know, the result gives the highest average output power at 1112nm generated by an 808 nm diode-end-pumped Nd:YAG laser.展开更多
Performance of an LD-end-pumped passively Q-switched Nd: YA G/Cr4+ : YA G microchip laser operating at 1123 nm is studied. A maximum average output power of 517row with an optical-to-optical conversion efficiency o...Performance of an LD-end-pumped passively Q-switched Nd: YA G/Cr4+ : YA G microchip laser operating at 1123 nm is studied. A maximum average output power of 517row with an optical-to-optical conversion efficiency of 12.6% and a slope efficiency of 25.8% is obtained under a pump power of 4.1 W. A minimum pulse width of 1.1 ns with a pulse repetition rate of 20.2kHz is obtained, and the corresponding pulse energy and peak power are 25.6μJ and 23.3kW, respectively. To our knowledge, the 23.3kW peak power is the highest among 1123nm lasers. Additionally, based on the 1123 nm laser, with LBO as the frequency doubler, a 288-mW green-yellow laser at 561 nm is successfully achieved.展开更多
The passively Q-switched and mode-locked(QML) characteristics in a diode-pumped Nd∶GdVO4 laser with Cr4+∶YAG saturable absorbers have been demonstrated. A maximum average output power of 710mW has been obtained in...The passively Q-switched and mode-locked(QML) characteristics in a diode-pumped Nd∶GdVO4 laser with Cr4+∶YAG saturable absorbers have been demonstrated. A maximum average output power of 710mW has been obtained in the QML laser. The maximum energy of a single Q-switched pulse is 52.5μJ, with the corresponding pulse width of 30ns and the peak power of 1.75kW, at the incident pump power of 7.75W. The repetition rates of the Q-switched envelope and the mode-locked laser pulse are 16.7kHz and 680MHz, respectively.展开更多
A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd:YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved....A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd:YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved. A maximum output power of as high as 612mW is obtained under a pump power of 20. 7 W and at a pulse repetition frequency rate of 20kHz, corresponding to an optical-to-optical conversion efficiency of 3%.展开更多
A diode-pumped doubly Q-switched Nd∶YAG laser operating at 1064nm both with an acoustic-optical(AO)modulator and Cr4+∶YAG saturable absorber in the cavity is demonstrated.At the incident pump power of 11.8W the lase...A diode-pumped doubly Q-switched Nd∶YAG laser operating at 1064nm both with an acoustic-optical(AO)modulator and Cr4+∶YAG saturable absorber in the cavity is demonstrated.At the incident pump power of 11.8W the laser can generate stable 8ns pulse with the peak power of 23.6kW at a 10kHz repetition rate.The pulse temporal profile is more symmetric and shorter compared with that of passively Q-switched lasers with only AO-active and Cr4+∶YAG.A reasonable analysis is developed to explain the experimental results theoretically.展开更多
Diode end-pumped solid-state lasers have the potential to yield high quality laser beams with high efficiency for laser range finding and warning receiver applications as well as day and night military laser designati...Diode end-pumped solid-state lasers have the potential to yield high quality laser beams with high efficiency for laser range finding and warning receiver applications as well as day and night military laser designation systems. In this paper we presents theoretical calculations using Advanced Dynamics Professional LASCAD software and experimental studies for a high power pigtailed fiber diode laser module of 8 W operating at 808 nm with a specially designed high efficiency cooling system, end pumped high-efficiency Nd:YVO4 laser of 3 × 3 × 10 mm rod and overall cavity length of 44 mm. To the best of our knowledge a self Q-switching effects was generated in Nd:YVO4 laser by changing the cavity dimensions and the position of the intracavity KTP crystal at certain regime of operation for the first time, in which the cavity length is reduced to be 30 mm and the distance between Nd:YVO4 rod and KTP crystal is only 1mm. Self Q-switched laser pulse at 532 nm with high peak power of 96 W, pulse width of 88 ns at FWHM and repetition rate of 400 kHz was achieved. Experimental studies of a passive Q-switched Nd:YVO4 laser using Cr:YAG crystal with three different transmissions of 30%, 40% and 70% were investigated. Passive Q-switched laser pulse at 1064 nm and narrow line width of less than 1.5 nm with highest peak power of nearly 18 kW, short pulse width of less than 4 ns at FWHM and higher repetition rate of 45 kHz using Cr:YAG with transmission of 30% was achieved for the first time.展开更多
Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations,...Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations, the time dependent laser equations have been solved numerically, whereas the space-dependent OPO equations analytically. Our results show that 1.4 J diode laser (810 nm) pulse with 200 msec width, delivers 30 mJ Nd:YAG laser (1064 nm) pulse with 5 n-second width. This Nd:YAG laser further generates 9 mJ eye safe signal (1570 nm) pulse with 2.5 n-second width.展开更多
A corner-pumped type is a new pumping type in the diode-pumped all-solid-state lasers, which has the advantages of high pump efficiency and favourable pump uniformity. A highly efficient corner-pumped Nd:YAG/YAG comp...A corner-pumped type is a new pumping type in the diode-pumped all-solid-state lasers, which has the advantages of high pump efficiency and favourable pump uniformity. A highly efficient corner-pumped Nd:YAG/YAG composite slab laser is demonstrated in this paper. The maximal continuous-wave output power of the 1064 nm laser is up to 18.57 W with a slope efficiency and an optical-to-optical conversion efficiency of 44.9% and 39.8%, respectively. Inserting an acousto-optic Q-switch in the cavity, the highest average output power of the quasi-continuous wave 1064 nm laser of 6.73W is obtained at a repetition rate of 9.26 kHz. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped all-solid-state lasers with low or medium output powers.展开更多
We report the specification of a compact and stable side diode-pumped Q-switched pulsed Nd:YAG laser. We ex- perimentally study and compare the performance of the pulsed Nd:YAG laser in the free-running and Q-switch...We report the specification of a compact and stable side diode-pumped Q-switched pulsed Nd:YAG laser. We ex- perimentally study and compare the performance of the pulsed Nd:YAG laser in the free-running and Q-switched modes at different pulse repetition rates from 1 Hz to 100 Hz. The laser output energy is stabilized by using a special configu- ration of the optical resonator. In this laser, an unsymmetrical concave-concave resonator is used and this structure helps the mode volume to be nearly fixed when the pulse repetition rate is increased. According to the experimental results in the Q-switched operation, the laser output energy is nearly constant around 70 mJ with an FWHM pulse width of 7 ns at 100 Hz. The optical-to-optical conversion efficiency in the Q-switched regime is 17.5%.展开更多
AIM: To evaluate whether the Q-switched Nd:YAG laser treatment applied in routine capsulotomy elicits oxidative stress in aqueous and vitreous humors. METHODS: Thirty-six patients who had to undergo a 25 gauge par...AIM: To evaluate whether the Q-switched Nd:YAG laser treatment applied in routine capsulotomy elicits oxidative stress in aqueous and vitreous humors. METHODS: Thirty-six patients who had to undergo a 25 gauge pars plana vitrectomy due to vitreoretinal disorders were enrolled, 15 of them underwent a Q-switched Nd:YAG laser capsulotomy 7 d before vitrectomy due to posterior capsule opacification(PCO)(Nd:YAG laser group) while the remaining 21 patients were not laser treated before vitrectomy(no Nd:YAG laser group). Samples of the aqueous and vitreous humors were collected during vitrectomy from all patients for the assessment of oxidative parameters which were compared between the Nd:YAG laser group and no Nd:YAG laser group. Thiobarbituric acid reactive substances(TBARS), a product of membrane lipid peroxidation, nitrite levels, the antioxidative activities of SOD and catalase, the 4-HNE-protein conjugate formation, indicating structural modifications in proteins due to lipoperoxidation, were assessed in aqueous and vitreous samples. RESULTS: In the human vitreous humor TBARS levels are significantly higher in the Nd:YAG laser group compared to the no Nd:YAG laser group and importantly, there is a significant correlation between the TBARS levels and the total energy of Nd:YAG laser used during capsulotomy.Moreover the anti-oxidative activities of SOD and catalase were significantly decreased by Nd:YAG laser treatment, both in aqueous and vitreous humors. In accordance with the TBARS data and anti-oxidative enzyme activities, significantly higher levels of proteins were conjugated with the lipoperoxidation product 4-HNE in the aqueous and vitreous humors in the Nd:YAG laser-treated group in comparison to no Nd:YAG laser group. CONCLUSION: These data, clearly suggest that any change that Q-switched Nd:YAG photo disruption may cause in the aqueous and vitreous compartments, resulting in a higher level of oxidative damage might be of considerable clinical significance particularly by accelerating the aging of the anterior and posterior segments of the eye and by worsening the intraocular pressure, the uveal, the retinal(especially macular) pathologies.展开更多
We demonstrated the highly efficient continuous wave (CW) and Q-switched infrared laser from a diode- side-pumped Nd:YAG crystal. A CW output as high as 66 W at 1319 nm was achieved under the pump power of 460 W, c...We demonstrated the highly efficient continuous wave (CW) and Q-switched infrared laser from a diode- side-pumped Nd:YAG crystal. A CW output as high as 66 W at 1319 nm was achieved under the pump power of 460 W, corresponding to a coversion efficiency of 14.3%. A maximum average power of 8.9 W of TEM00 mode was obtained in Q-switched operation at the repetition rate of 8 kHz. The performance of the laser considering the thermal lens effect induced by pump power was also analyzed.展开更多
We report on the design, realization, and output performance of a diode-pumped high-peak-power passively Q-switched Nd:YAG∕Cr^(4+):YAG composite medium monolithic laser with four-beam output. The energy of a laser pu...We report on the design, realization, and output performance of a diode-pumped high-peak-power passively Q-switched Nd:YAG∕Cr^(4+):YAG composite medium monolithic laser with four-beam output. The energy of a laser pulse was higher than 3 m J with duration of 0.9 ns. The proposed system has the ability to choose independently the focus of each beam. Such a laser device can be used for multipoint ignition of an automobile gasoline engine, but could also be of interest for ignition in space propulsion or in turbulent conditions specific to aeronautics.展开更多
We demonstrate a high-pulse-energy, short-pulse-width passively Q-switched(PQS) Nd:YAG∕V3t:YAG laser at 1.3 μm, which is end-pumped by a pulsed laser diode. During the PQS regime, a maximum total output pulse en...We demonstrate a high-pulse-energy, short-pulse-width passively Q-switched(PQS) Nd:YAG∕V3t:YAG laser at 1.3 μm, which is end-pumped by a pulsed laser diode. During the PQS regime, a maximum total output pulse energy of 3.3 m J is obtained under an absorbed pump pulse energy of 21.9 m J. Up to 400 μJ single-pulse energy is realized with the shortest pulse width of 6.16 ns and a pulse repetition frequency of 34.1 k Hz,corresponding to a peak power of 64.9 k W. The high-energy laser pulse is operated in the dual wavelengths of 1319 and 1338 nm, which is a potential laser source for THz generation.展开更多
By modulating the pump current, we developed a passively Q-switched diode-pumped all-solid-state laser with a repetition rate stabilized up to 10^-7. It was experimentally demonstrated that the stability could sustain...By modulating the pump current, we developed a passively Q-switched diode-pumped all-solid-state laser with a repetition rate stabilized up to 10^-7. It was experimentally demonstrated that the stability could sustain for an arbitrarily long time. Moreover, the stabilized repetition rates which were synchronized with different modulating frequencies were tuneable in a wide range, by adjusting the period of the pumping cycle only. The output single-pulse energy was also stabilized, which was independent on the pump power after reaching a saturable value.展开更多
We demonstrate a three-nanosecond equidistant sub-pulse multi-step Q-switched Nd:Y3 Al5 O12(Nd:YAG) laser.In the time interval of 100–1000 ns, three pulses with the same nanosecond interval and the same peak power ar...We demonstrate a three-nanosecond equidistant sub-pulse multi-step Q-switched Nd:Y3 Al5 O12(Nd:YAG) laser.In the time interval of 100–1000 ns, three pulses with the same nanosecond interval and the same peak power are obtained at the pulse width of 24 ns, 28 ns, and 36.6 ns, respectively.The energy is 32.5 m J, and the optical efficiency is 10.8%.The multi-step Q-switched method does not require the insertion of other optical elements into the traditional Q-switched laser, and it is very suitable to obtain pulse group output with several nanosecond pulse intervals.展开更多
A high precision laser trigger system is built up in the single test module of Primary Test Stand (PTS) facility. A fourth harmonic, with a wavelength A of 266 nm, Q-switched Nd:YAG laser was used to trigger the 5 ...A high precision laser trigger system is built up in the single test module of Primary Test Stand (PTS) facility. A fourth harmonic, with a wavelength A of 266 nm, Q-switched Nd:YAG laser was used to trigger the 5 MV multi-gap multi-channel gas switch which was filled with high pressure SF6-N2 mixture gas. The maximum deviation and the standard deviation in the jitter time of the trigger system is 4- 0.7 ns and 0.3 ns respectively. The maximum deviation and the standard deviation in the jitter time for the multi-gap multi-channel laser triggering switch is 4- 2.4 ns and 1.5 ns respectively. The curve of switch delay-time versus laser energy is obtained, which is helpful for the choice of fitting laser energy. The successful test with two lasers indicated that the design of using twenty-four lasers to trigger twenty-four switches respectively is feasible in "PTS".展开更多
A diode-end-pumped Nd:YAG dual-wavelength laser operating at 1319 and 1338 nm is demonstrated. The maximum average output power of the quasi-continuous wave linearly polarized dual-wavelength laser is obtained to be ...A diode-end-pumped Nd:YAG dual-wavelength laser operating at 1319 and 1338 nm is demonstrated. The maximum average output power of the quasi-continuous wave linearly polarized dual-wavelength laser is obtained to be 2.1 W at a repetition rate of 50 kHz with an output power instability of less than 0.38% and beam quality factor M^2 of 1.45. Using the two lines, the highly coherent and narrow linewidth terahertz radiation of 3.23 THz can be generated in an organic 4-N, N-dimethylamino-methyl-stilbazolium tosylate (DAST) crystal. Meanwhile, the multi-wavelength red laser at 659.5, 664 and 669 nm is generated by frequency doubling and sum frequency processes in a lithium triborate (LBO) crystal. The average red laser output power is enhanced up to 1.625 W at a repetition rate of 15 kHz with an output power instability of better than 0.53% and beam quality factor M^2 of 6.05. Using the three lines, it is possible to generate the multi-wavelength THz radiation of 3.3, 3.43 and 6.73 THz in an appropriate difference frequency crystal.展开更多
Objective:Q-switched lasers,including 1064-nm Nd:YAG nansecond laser (QSNYL),755-nm alexandrite nanosecond laser (QSAL),and 694-nm nanosecond ruby laser (QSRL),are clinically available for the treatment of acquired bi...Objective:Q-switched lasers,including 1064-nm Nd:YAG nansecond laser (QSNYL),755-nm alexandrite nanosecond laser (QSAL),and 694-nm nanosecond ruby laser (QSRL),are clinically available for the treatment of acquired bilateral nevus of Ota-like macules (ABNOM).However,no reliable evidence from large-scale comparative studies identifies which type of laser works best.This study aims to determine the differences in the effectiveness,complications,and risk factors of QSNYL,QSAL,and QSRL in the treatment of ABNOM,further to provide evidence for clinician to make optimal choice according to the condition of patients.Methods:We collected the data from 685 ABNOM patients,including clinical features,medical treatments,and follow-up,since 1999 to 2014.The Kruskal-Wallis test was used to compare therapeutic differences between the three groups.The risk factors were analyzed using univariate analysis (x2 test) and multivariate logistic regression analysis.Results:The overall treatment efficiency of the QSNYL group (52.5%) and QSAL group (51.9%) was higher than that of the QSRL group (39.5%) (x2 =17.468,P < 0.001).The onset time of the QSRL and QSAL groups was shorter than that of the QSNYL group.The factors influencing efficacy in the QSNYL group were age at first treatment,number of treatments,coexistence with melesma,and the presence of hyperpigmentation;in the QSAL group was the number of treatments;and in the QSRL group was the number of treatments and hyperpigmentation.The prevalence of hyperpigrnentation in the QSNYL group (30.5%) and the QSAL group (27.5%) was lower than that of the QSRL group (47.3%) (X2=6.576,P<0.001).Concluslon:The QSNYL,QSAL,and QSRL are all effective and safe treatments for ABNOM.Considering the overall efficacy,duration of treatment,side effects,and risk factors,the QSAL is an optimal choice for ABNOM treatment.展开更多
基金Project supported by the Fund from Nanjing University of Posts and Telecommunications,China(Grant Nos.JUH219002 and JUH219007)the Key Research and Development Program of Shandong Province,China(Grant No.2021CXGC010202)。
文摘A high-performance LED-side-pumped two-rod Nd,Ce:YAG laser with continuous-wave(CW) and acousto–optical(A-O) Q-switched operation is demonstrated in this work. A symmetrically shaped flat–flat cavity with two identical LEDside-pumped laser modules is employed for power scalability. In the CW regime, the maximum output average power of laser at 1064 nm is 4.41 W, corresponding to a maximum optical conversion efficiency of 5.3% and a slope efficiency is 12.4%. In the active Q-switched regime, the pulse energy of laser reaches as high as 0.89 m J at a repetition rate of 800 Hz with a pulse width of 457.2 ns, the corresponding highest peak output power is 1.94 k W and the M~2 factor is measured to be about 8.8. To the best of the authors' knowledge, this is the first demonstration and the highest performance of a CW LED-side-pumped two-rod laser Nd,Ce:YAG with Watt-level output reported so far.
基金Supported by the National Basic Research Program of China under Grant No 2013CB632704
文摘A diode-end-pumped Q-switched high-efficiency Nd, Cr:YAG laser with simultaneous dual-wavelength emission at 946nm and 1.3μm is demonstrated. The maximum output power of 1.93 W with simultaneous dual-wavelength operation is achieved at an absorbed pump power of 13.32 W and an absorbed slope efficiency of 15.15%. The maximum optical-optical efficiency is 14.49% with pulse widths of 16.38ns at 946nm and 26.65ns at 1.3μm. A maximum total repetition rate of 43.25 kHz is obtained.
基金Supported by the Natural Science Foundation of Shandong Province under Grant Nos ZR2015FM018 and ZR2014FM028the National Natural Science Foundation of China under Grant No 61475086
文摘A high-power passively Q-switched Nd:YAG laser operating at lll2nm with Cr4+:yAO as a saturable absorber is demonstrated. Under 808 nm diode-direct pumping, the maximum average output power of 2.73 W is achieved at the pump power of 16.65 W, corresponding to an optical-to-optical conversion efficiency of 16.4%. At the same time, the pulse width, pulse repetition rate, single pulse energy and peak power are 27.2ns, 9 kHz, 303.3#3 and 11.2kW, respectively. As far as we know, the result gives the highest average output power at 1112nm generated by an 808 nm diode-end-pumped Nd:YAG laser.
基金Supported by the Foundation of Shandong Province under Grant No J13LN28the National Natural Science Foundation of China under Grant No 11304184
文摘Performance of an LD-end-pumped passively Q-switched Nd: YA G/Cr4+ : YA G microchip laser operating at 1123 nm is studied. A maximum average output power of 517row with an optical-to-optical conversion efficiency of 12.6% and a slope efficiency of 25.8% is obtained under a pump power of 4.1 W. A minimum pulse width of 1.1 ns with a pulse repetition rate of 20.2kHz is obtained, and the corresponding pulse energy and peak power are 25.6μJ and 23.3kW, respectively. To our knowledge, the 23.3kW peak power is the highest among 1123nm lasers. Additionally, based on the 1123 nm laser, with LBO as the frequency doubler, a 288-mW green-yellow laser at 561 nm is successfully achieved.
文摘The passively Q-switched and mode-locked(QML) characteristics in a diode-pumped Nd∶GdVO4 laser with Cr4+∶YAG saturable absorbers have been demonstrated. A maximum average output power of 710mW has been obtained in the QML laser. The maximum energy of a single Q-switched pulse is 52.5μJ, with the corresponding pulse width of 30ns and the peak power of 1.75kW, at the incident pump power of 7.75W. The repetition rates of the Q-switched envelope and the mode-locked laser pulse are 16.7kHz and 680MHz, respectively.
基金Supported by the Foundation of the State Key Laboratory of Crystal Material of Shandong University under Grant No KF1101the Foundation of Shandong University under Grant No 1170072613176+2 种基金the National Natural Science Foundation of China under Grant Nos 11004122 and 11204160the Special Grade of China Postdoctoral Science Foundation under Grant No 201104627the Independent Innovation Foundation of Shandong University under Grant No 2011GN058
文摘A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd:YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved. A maximum output power of as high as 612mW is obtained under a pump power of 20. 7 W and at a pulse repetition frequency rate of 20kHz, corresponding to an optical-to-optical conversion efficiency of 3%.
基金Science and Technology Key Projects Plan of Shandong Province
文摘A diode-pumped doubly Q-switched Nd∶YAG laser operating at 1064nm both with an acoustic-optical(AO)modulator and Cr4+∶YAG saturable absorber in the cavity is demonstrated.At the incident pump power of 11.8W the laser can generate stable 8ns pulse with the peak power of 23.6kW at a 10kHz repetition rate.The pulse temporal profile is more symmetric and shorter compared with that of passively Q-switched lasers with only AO-active and Cr4+∶YAG.A reasonable analysis is developed to explain the experimental results theoretically.
文摘Diode end-pumped solid-state lasers have the potential to yield high quality laser beams with high efficiency for laser range finding and warning receiver applications as well as day and night military laser designation systems. In this paper we presents theoretical calculations using Advanced Dynamics Professional LASCAD software and experimental studies for a high power pigtailed fiber diode laser module of 8 W operating at 808 nm with a specially designed high efficiency cooling system, end pumped high-efficiency Nd:YVO4 laser of 3 × 3 × 10 mm rod and overall cavity length of 44 mm. To the best of our knowledge a self Q-switching effects was generated in Nd:YVO4 laser by changing the cavity dimensions and the position of the intracavity KTP crystal at certain regime of operation for the first time, in which the cavity length is reduced to be 30 mm and the distance between Nd:YVO4 rod and KTP crystal is only 1mm. Self Q-switched laser pulse at 532 nm with high peak power of 96 W, pulse width of 88 ns at FWHM and repetition rate of 400 kHz was achieved. Experimental studies of a passive Q-switched Nd:YVO4 laser using Cr:YAG crystal with three different transmissions of 30%, 40% and 70% were investigated. Passive Q-switched laser pulse at 1064 nm and narrow line width of less than 1.5 nm with highest peak power of nearly 18 kW, short pulse width of less than 4 ns at FWHM and higher repetition rate of 45 kHz using Cr:YAG with transmission of 30% was achieved for the first time.
文摘Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations, the time dependent laser equations have been solved numerically, whereas the space-dependent OPO equations analytically. Our results show that 1.4 J diode laser (810 nm) pulse with 200 msec width, delivers 30 mJ Nd:YAG laser (1064 nm) pulse with 5 n-second width. This Nd:YAG laser further generates 9 mJ eye safe signal (1570 nm) pulse with 2.5 n-second width.
基金Project supported by the Postdoctoral Science Foundation,China (Grant No 20090450370)
文摘A corner-pumped type is a new pumping type in the diode-pumped all-solid-state lasers, which has the advantages of high pump efficiency and favourable pump uniformity. A highly efficient corner-pumped Nd:YAG/YAG composite slab laser is demonstrated in this paper. The maximal continuous-wave output power of the 1064 nm laser is up to 18.57 W with a slope efficiency and an optical-to-optical conversion efficiency of 44.9% and 39.8%, respectively. Inserting an acousto-optic Q-switch in the cavity, the highest average output power of the quasi-continuous wave 1064 nm laser of 6.73W is obtained at a repetition rate of 9.26 kHz. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped all-solid-state lasers with low or medium output powers.
文摘We report the specification of a compact and stable side diode-pumped Q-switched pulsed Nd:YAG laser. We ex- perimentally study and compare the performance of the pulsed Nd:YAG laser in the free-running and Q-switched modes at different pulse repetition rates from 1 Hz to 100 Hz. The laser output energy is stabilized by using a special configu- ration of the optical resonator. In this laser, an unsymmetrical concave-concave resonator is used and this structure helps the mode volume to be nearly fixed when the pulse repetition rate is increased. According to the experimental results in the Q-switched operation, the laser output energy is nearly constant around 70 mJ with an FWHM pulse width of 7 ns at 100 Hz. The optical-to-optical conversion efficiency in the Q-switched regime is 17.5%.
基金Supported by Public Universitary Funds(NUZR_autof_17_01)of University of Torinothe Italian Ministry for Research MIUR(No.2010C2LKKJ-007+1 种基金No.20154JRJPP-005)the Ph D and Post-doc Program of the University of Torino
文摘AIM: To evaluate whether the Q-switched Nd:YAG laser treatment applied in routine capsulotomy elicits oxidative stress in aqueous and vitreous humors. METHODS: Thirty-six patients who had to undergo a 25 gauge pars plana vitrectomy due to vitreoretinal disorders were enrolled, 15 of them underwent a Q-switched Nd:YAG laser capsulotomy 7 d before vitrectomy due to posterior capsule opacification(PCO)(Nd:YAG laser group) while the remaining 21 patients were not laser treated before vitrectomy(no Nd:YAG laser group). Samples of the aqueous and vitreous humors were collected during vitrectomy from all patients for the assessment of oxidative parameters which were compared between the Nd:YAG laser group and no Nd:YAG laser group. Thiobarbituric acid reactive substances(TBARS), a product of membrane lipid peroxidation, nitrite levels, the antioxidative activities of SOD and catalase, the 4-HNE-protein conjugate formation, indicating structural modifications in proteins due to lipoperoxidation, were assessed in aqueous and vitreous samples. RESULTS: In the human vitreous humor TBARS levels are significantly higher in the Nd:YAG laser group compared to the no Nd:YAG laser group and importantly, there is a significant correlation between the TBARS levels and the total energy of Nd:YAG laser used during capsulotomy.Moreover the anti-oxidative activities of SOD and catalase were significantly decreased by Nd:YAG laser treatment, both in aqueous and vitreous humors. In accordance with the TBARS data and anti-oxidative enzyme activities, significantly higher levels of proteins were conjugated with the lipoperoxidation product 4-HNE in the aqueous and vitreous humors in the Nd:YAG laser-treated group in comparison to no Nd:YAG laser group. CONCLUSION: These data, clearly suggest that any change that Q-switched Nd:YAG photo disruption may cause in the aqueous and vitreous compartments, resulting in a higher level of oxidative damage might be of considerable clinical significance particularly by accelerating the aging of the anterior and posterior segments of the eye and by worsening the intraocular pressure, the uveal, the retinal(especially macular) pathologies.
基金the National Natural Science Foundation of China under Grant No.60478009
文摘We demonstrated the highly efficient continuous wave (CW) and Q-switched infrared laser from a diode- side-pumped Nd:YAG crystal. A CW output as high as 66 W at 1319 nm was achieved under the pump power of 460 W, corresponding to a coversion efficiency of 14.3%. A maximum average power of 8.9 W of TEM00 mode was obtained in Q-switched operation at the repetition rate of 8 kHz. The performance of the laser considering the thermal lens effect induced by pump power was also analyzed.
基金Autoritatea Nationala pentru Cercetare Stiintifica(ANCS)(PN-II-PT-PCCA-2011-3.2-1040(58/2012),NUCLEU4N/2016)Horizon 2020(691688 LASIG-TWIN)
文摘We report on the design, realization, and output performance of a diode-pumped high-peak-power passively Q-switched Nd:YAG∕Cr^(4+):YAG composite medium monolithic laser with four-beam output. The energy of a laser pulse was higher than 3 m J with duration of 0.9 ns. The proposed system has the ability to choose independently the focus of each beam. Such a laser device can be used for multipoint ignition of an automobile gasoline engine, but could also be of interest for ignition in space propulsion or in turbulent conditions specific to aeronautics.
基金supported by the National Natural Science Foundation of China(Grant Nos.61275142 12751426,1308042,31608042,and 51321091)the China Postdoctoral Science Foundation(Grant No.2014T70633)the Foundation for Outstanding Young Scientists in Shandong Province(Grant No.BS2012ZZ001)
文摘We demonstrate a high-pulse-energy, short-pulse-width passively Q-switched(PQS) Nd:YAG∕V3t:YAG laser at 1.3 μm, which is end-pumped by a pulsed laser diode. During the PQS regime, a maximum total output pulse energy of 3.3 m J is obtained under an absorbed pump pulse energy of 21.9 m J. Up to 400 μJ single-pulse energy is realized with the shortest pulse width of 6.16 ns and a pulse repetition frequency of 34.1 k Hz,corresponding to a peak power of 64.9 k W. The high-energy laser pulse is operated in the dual wavelengths of 1319 and 1338 nm, which is a potential laser source for THz generation.
基金This work was partly supported by the Shanghai Pri-ority Academic Discipline, the National Key Project forBasic Research (No. TG1999075204) the NationalNatural Science Foundation of China (No. 10374028).
文摘By modulating the pump current, we developed a passively Q-switched diode-pumped all-solid-state laser with a repetition rate stabilized up to 10^-7. It was experimentally demonstrated that the stability could sustain for an arbitrarily long time. Moreover, the stabilized repetition rates which were synchronized with different modulating frequencies were tuneable in a wide range, by adjusting the period of the pumping cycle only. The output single-pulse energy was also stabilized, which was independent on the pump power after reaching a saturable value.
基金supported by the National Natural Science Foundation of China (NSFC)(No.11974060)the Natural Science Foundation of Jilin Province (No.20190201266JC)。
文摘We demonstrate a three-nanosecond equidistant sub-pulse multi-step Q-switched Nd:Y3 Al5 O12(Nd:YAG) laser.In the time interval of 100–1000 ns, three pulses with the same nanosecond interval and the same peak power are obtained at the pulse width of 24 ns, 28 ns, and 36.6 ns, respectively.The energy is 32.5 m J, and the optical efficiency is 10.8%.The multi-step Q-switched method does not require the insertion of other optical elements into the traditional Q-switched laser, and it is very suitable to obtain pulse group output with several nanosecond pulse intervals.
基金supported by National Natural Science Foundation of China (No.10574096)the Research Fund for the Doctoral Program of Higher Education of China (No.20050610010)
文摘A high precision laser trigger system is built up in the single test module of Primary Test Stand (PTS) facility. A fourth harmonic, with a wavelength A of 266 nm, Q-switched Nd:YAG laser was used to trigger the 5 MV multi-gap multi-channel gas switch which was filled with high pressure SF6-N2 mixture gas. The maximum deviation and the standard deviation in the jitter time of the trigger system is 4- 0.7 ns and 0.3 ns respectively. The maximum deviation and the standard deviation in the jitter time for the multi-gap multi-channel laser triggering switch is 4- 2.4 ns and 1.5 ns respectively. The curve of switch delay-time versus laser energy is obtained, which is helpful for the choice of fitting laser energy. The successful test with two lasers indicated that the design of using twenty-four lasers to trigger twenty-four switches respectively is feasible in "PTS".
基金supported by the National Basic Research Program of China (Grant No 2007CB310403)the Tianjin Municipal Primary application and Frontier Technology Research Plan,China (Grant No 07JCYBJC06200)
文摘A diode-end-pumped Nd:YAG dual-wavelength laser operating at 1319 and 1338 nm is demonstrated. The maximum average output power of the quasi-continuous wave linearly polarized dual-wavelength laser is obtained to be 2.1 W at a repetition rate of 50 kHz with an output power instability of less than 0.38% and beam quality factor M^2 of 1.45. Using the two lines, the highly coherent and narrow linewidth terahertz radiation of 3.23 THz can be generated in an organic 4-N, N-dimethylamino-methyl-stilbazolium tosylate (DAST) crystal. Meanwhile, the multi-wavelength red laser at 659.5, 664 and 669 nm is generated by frequency doubling and sum frequency processes in a lithium triborate (LBO) crystal. The average red laser output power is enhanced up to 1.625 W at a repetition rate of 15 kHz with an output power instability of better than 0.53% and beam quality factor M^2 of 6.05. Using the three lines, it is possible to generate the multi-wavelength THz radiation of 3.3, 3.43 and 6.73 THz in an appropriate difference frequency crystal.
基金supported by grants from National Nature Science Foundation of China(No.81502739)Jiang Su National Nature Science Foundation(No.BK20150068)Medical Science and Technology Innovation Project of Chinese Academy of Medical Sciences(No.CIFMS-2017-I2M-1-017)
文摘Objective:Q-switched lasers,including 1064-nm Nd:YAG nansecond laser (QSNYL),755-nm alexandrite nanosecond laser (QSAL),and 694-nm nanosecond ruby laser (QSRL),are clinically available for the treatment of acquired bilateral nevus of Ota-like macules (ABNOM).However,no reliable evidence from large-scale comparative studies identifies which type of laser works best.This study aims to determine the differences in the effectiveness,complications,and risk factors of QSNYL,QSAL,and QSRL in the treatment of ABNOM,further to provide evidence for clinician to make optimal choice according to the condition of patients.Methods:We collected the data from 685 ABNOM patients,including clinical features,medical treatments,and follow-up,since 1999 to 2014.The Kruskal-Wallis test was used to compare therapeutic differences between the three groups.The risk factors were analyzed using univariate analysis (x2 test) and multivariate logistic regression analysis.Results:The overall treatment efficiency of the QSNYL group (52.5%) and QSAL group (51.9%) was higher than that of the QSRL group (39.5%) (x2 =17.468,P < 0.001).The onset time of the QSRL and QSAL groups was shorter than that of the QSNYL group.The factors influencing efficacy in the QSNYL group were age at first treatment,number of treatments,coexistence with melesma,and the presence of hyperpigmentation;in the QSAL group was the number of treatments;and in the QSRL group was the number of treatments and hyperpigmentation.The prevalence of hyperpigrnentation in the QSNYL group (30.5%) and the QSAL group (27.5%) was lower than that of the QSRL group (47.3%) (X2=6.576,P<0.001).Concluslon:The QSNYL,QSAL,and QSRL are all effective and safe treatments for ABNOM.Considering the overall efficacy,duration of treatment,side effects,and risk factors,the QSAL is an optimal choice for ABNOM treatment.