We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that t...We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.展开更多
We demonstrate antimonene as a saturable absorber(SA) to generate an ultrafast mode-locked and Q-switched laser in the 2 μm wavelength region. The two antimonene-based SAs were prepared and inserted separately in a t...We demonstrate antimonene as a saturable absorber(SA) to generate an ultrafast mode-locked and Q-switched laser in the 2 μm wavelength region. The two antimonene-based SAs were prepared and inserted separately in a thulium–holmiumdoped fiber laser to produce the pulsed laser. Antimonene was coated onto a tapered fiber to generate soliton mode-locked pulses and used in thin-film form for the generation of Q-switched pulses. The mode-locking was stable within a pump power of 267 m W–511 m W, and the laser operated at a central wavelength of 1897.4 nm. The mode-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 MHz, with a signal-to-noise ratio of 64 d B. Q-switched laser operation was stable at a wavelength of 1890.1 nm within a pump power of 312 m W–381 m W. With the increase in pump power from 312 m W to 381 m W, the repetition rate increased to a maximum of 56.63 k Hz and the pulse width decreased to a minimum value of 2.85 μs. Wide-range tunability of the Q-switched laser was also realized within the wavelength range of1882 nm–1936 nm.展开更多
We report a high repetition frequency, high power stability and low laser noise laser-diode(LD) end-pumped Nd: YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-polyvinyl alcohol(PVA) film ...We report a high repetition frequency, high power stability and low laser noise laser-diode(LD) end-pumped Nd: YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-polyvinyl alcohol(PVA) film as a saturable absorber(SA). A Brewster polarizer(BP) and a birefringent crystal(BC) are incorporated to enable frequency selection and filtering for the passively Q-switched 1123 nm pulsed laser to improve the power stability and reduce the noise. When the pump power is 5.1 W, an average output power of 457.9 m W is obtained, corresponding to a repetition frequency of 1.09 MHz,a pulse width of 56 ns, a spectral line width of 0.65 nm, a power instability of ±0.92%, and a laser noise of 0.89%.The successful implementation of the “Ti_(3)C_(2)T_(x)-PVA film passively Q-switching” combined with “frequency selection and filtering of BP + BC” technology path provides a valuable reference for developing pulsed laser with high repetition frequency, high stability and low noise.展开更多
We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 ...We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 W were acquired from the Tm, Ho:LuVO4 laser with the pump power of 14.55 W, corresponding to a pulse width of 2.89 μs,a pulse repetition rate of 71.84 kHz, and a pulse energy of about 6.70 μJ.展开更多
A transmission-type tungsten disulfide(WS_2)-based saturable absorber(SA) is fabricated and applied to passively Q-switched Nd:YVO_4 laser.The WS_2 nanosheets are deposited on a quartz substrate by the vertical evapor...A transmission-type tungsten disulfide(WS_2)-based saturable absorber(SA) is fabricated and applied to passively Q-switched Nd:YVO_4 laser.The WS_2 nanosheets are deposited on a quartz substrate by the vertical evaporation method.By inserting the WS2 SA into the plano-concave laser cavity,we achieve 153-ns pulses with an average output power of1.19 W at 1064 nm.To the best of our knowledge,both of them are the best results among those obtained by the Q-switched solid-state lasers with WS_2-based absorbers.The repetition rate ranges from 1.176 MHz to 1.578 MHz.As far as we know,it is the first time that MHz level Q-switched pulses have been generated in all solid state lasers based on low-dimensional materials so far.展开更多
We demonstrate a passively Q-switched erbium-doped fiber laser(EDFL)using a copper nanoparticle(CuNP)thin film as the saturable absorber in a ring cavity.A stable Q-switched pulse operation is observed as the CuNP sat...We demonstrate a passively Q-switched erbium-doped fiber laser(EDFL)using a copper nanoparticle(CuNP)thin film as the saturable absorber in a ring cavity.A stable Q-switched pulse operation is observed as the CuNP saturable absorber(SA)is introduced in the cavity.The pulse repetition rate of the EDFL is observed to be proportional to the pump power,and is limited to 101.2 kHz by the maximum pump power of 113.7 mW.On the other hand,the pulse width reduces from 10.19 ps to 4.28 ps as the pump power is varied from 26.1 mW to 113.7 mW.The findings suggest that CuNP SA could be useful as a potential saturable absorber for the development of the robust,compact,efficient and low cost Q-switched fiber laser operating at 1.5-μm region.展开更多
In this paper, the effect of injected energy on low energy single longitudinal mode (SLM) pre-lase Q-switched is analyzed and the optimization procedure is shown in detail. Here, taking the Pr:YLF laser as an example ...In this paper, the effect of injected energy on low energy single longitudinal mode (SLM) pre-lase Q-switched is analyzed and the optimization procedure is shown in detail. Here, taking the Pr:YLF laser as an example of low energy laser, and the parameters of Pr:YLF laser by using pre-lase have been shown. Compared with normal Q-switched laser, the single pulse energy reaches 60.16% and the pulse width exceeds 39.73% when the same maximum energy is injected and SLM is achieved in pre-lase. The analysis results show that pre-lase is suitable for low energy laser to obtain SLM and there be an optimal performance to achieve the optimal energy output.展开更多
A Q-switched erbium-doped fiber laser(EDFL)incorporating zinc-oxide(ZnO)nanoparticles-based saturable absorber(SA)is proposed and demonstrated.To form the SA,the ZnO nanoparticles,which are originally in the powder fo...A Q-switched erbium-doped fiber laser(EDFL)incorporating zinc-oxide(ZnO)nanoparticles-based saturable absorber(SA)is proposed and demonstrated.To form the SA,the ZnO nanoparticles,which are originally in the powder form,are first dissolved in ethanol and subsequently deposited onto the surface of fiber ferrule by using the adhesion effect with the evaporation technique.By integrating the ZnO nanoparticle-based SA into a laser cavity of an EDFL,a self-started and stable Q-switching is achieved at a low threshold power of 20.24 mW.As the pump power is increased,the pulse repetition rate is tunable from 10.34 kHz to 25.59 kHz while pulse duration decreases from 21.39μs to 3.65μs.Additionally,this Q-switched laser has a maximum energy per pulse of 19.34 nJ and an average output power of 0.46 mW.These results indicate the feasibility and functionality of the ZnO nanoparticles-based SA for Q-switched generation,which offers the flexibility and easy integration of the SA into a ring laser cavity.展开更多
A black phosphorus(BP) saturable absorber(SA) solution with different concentrations(1.0 and 0.5 mg/ml) is fabricated with the liquid-phase exfoliation method. By using the BP-SA, a compact diode-pumped passively Q-sw...A black phosphorus(BP) saturable absorber(SA) solution with different concentrations(1.0 and 0.5 mg/ml) is fabricated with the liquid-phase exfoliation method. By using the BP-SA, a compact diode-pumped passively Q-switched Nd:YVO_4 laser is demonstrated. One reflecting Bragg gratings is used as the output coupler for mode selection. By inserting those BP-SA solutions in the laser cavity, the maximum single longitude mode,Q-switched output powers of 126 mW at 692.5 kHz and 149 mW at 630.3 kHz are achieved at the pump power of 8.0 W, corresponding to the pulse durations of 144 ns and 196 ns, respectively. Moreover, longitudinal-mode characteristics of Q-switched output laser in different optical cavity lengths based on two-kind BP-SA solution concentrations are investigated. Our results show that BP-SA could also be developed as an effective SA for the Q-switched, single longitudinal mode pulse laser.展开更多
Fe^2+:ZnSe thin films are prepared on sapphire substrate at room temperature by electron beam evaporation and then annealed in vacuum(about 1×10^-4 Pa)at different temperatures.The influences of thermal annealing...Fe^2+:ZnSe thin films are prepared on sapphire substrate at room temperature by electron beam evaporation and then annealed in vacuum(about 1×10^-4 Pa)at different temperatures.The influences of thermal annealing on the structural and optical properties of these films such as grain size and optical transmittance are investigated.The x-ray diffraction patterns show that the Fe2+:ZnSe thin film is preferred to be oriented along the(111)plane at different annealing temperatures.After the film is annealed,the full-width-at-half-maximum(FWHM)of the x-ray diffraction peak profile(111)of the film decreases and its crystal quality is improved.Scanning electron microscope images show that the films are more dense after being annealed.Finally,the sample is used as a saturable absorber in ZBLAN fiber laser.The annealed Fe^2+:ZnSe thin films can be used to realize stable Q-switching modulation on ZBLAN fiber laser.The results demonstrate that the Fe2+:ZnSe thin film is a promising material for generating the high-power pulses of mid-infrared Q-switched fiber lasers.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
We demonstrate a Q-switched erbium-doped fiber laser(EDFL) using a newly developed zinc oxide-(ZnO) based saturable absorber(SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol)film....We demonstrate a Q-switched erbium-doped fiber laser(EDFL) using a newly developed zinc oxide-(ZnO) based saturable absorber(SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol)film. A small piece of the film is then sandwiched between two fiber ferrules and is incorporated in an EDFL cavity for generating a stable Q-switching pulse train. The EDFL operates at 1560.4 nm with a pump power threshold of 11.8 mW, a pulse repetition rate tunable from 22.79 to 61.43 kHz, and the smallest pulse width of 7.00 μs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 62 dB indicating the high stability of the laser. These results show that the ZnO powder has a great potential to be used for pulsed laser applications.展开更多
A cw operation and a passively Q-switched(PQS) Ho:SSO laser(Cr^(2+):ZnSe as a saturable absorber) end-pumped by a Tm:YAP laser operating at near room temperature are reported. It is the first time to report a PQS Ho:S...A cw operation and a passively Q-switched(PQS) Ho:SSO laser(Cr^(2+):ZnSe as a saturable absorber) end-pumped by a Tm:YAP laser operating at near room temperature are reported. It is the first time to report a PQS Ho:SSO laser. For the cw mode, a maximum cw output power of 3.0 W is obtained, corresponding to a slope effciency of31.4%. For the PQS mode, a Cr^(2+):ZnSe is used as the saturable absorber, with transmission of 88.4% at 2112 nm.A maximum pulse energy of 1.29 mJ is obtained, corresponding to the pulse repetition frequency of 2.42 kHz. In this study, we change the distance between:Cr^(2+):ZnSe and the output mirror to research the pulse characteristic of the PQS Ho:SSO laser. The minimum pulse width of 73.5 ns is obtained, corresponding to the pulse energy of0.9 mJ and the pulse repetition frequency of 2.65 kHz.展开更多
Background: Previously described methods for removal of tattoos are chemical, mechanical, surgical, termal and laser assited methods. Invention of the Q-switch mode, advanced the laser method, to be one of the most ef...Background: Previously described methods for removal of tattoos are chemical, mechanical, surgical, termal and laser assited methods. Invention of the Q-switch mode, advanced the laser method, to be one of the most effective methods of tattoo removal. Objective: Comparing the tattoo removal and rate of lymphatic elimination of 3 different wavelengths of Q-switched Nd-YAG laser (532nm, 1064nm, combination 532 + 1064). Methods: In this study we examined lymphatic elimination and the effect of 532 nm, 1064 nm, and the combination (532 + 1064 nm) wavelength of laser pulse for the possible lymphatic cleansing mechanism of black pigmented tattoos. This study was performed on 18 New-Zealand rabbits, black pigmented tattoos were engraved on the back and the four extremities of the animals. 532 nm wavelength of Q switched Nd: YAG laser beam was applied on the left upper and bilateral lower extremities of the rabbits. During this period, excisional skin biopsies and lymph node biopsies were performed on days 7, 14 and 21. Results: Day 21 lymph node biopsies revealed mixed type of reactive hyperplasia and intracellular pigments were markedly seen in the laser treatment group and no intracellular tattoo pigment was seen in the control group. Conclusion: The findingd of this study indicate that lymphatic elimination may be one of the significant mechanisms of tattoo removal and the application of different wavelengths of Q-switched Nd-YAG laser do not show statistically significant differences in tattoo removal.展开更多
A two-dimensional silver nanoplate is prepared with the seed-mediated growth method and is used for achieving pulse fiber laser operation. By controlling the dimension parameters of the silver nanoplate, the surface p...A two-dimensional silver nanoplate is prepared with the seed-mediated growth method and is used for achieving pulse fiber laser operation. By controlling the dimension parameters of the silver nanoplate, the surface plasmon resonance absorption peak of the material is successfully adjusted to 1068 nm. Based on the silver nanoplate as a saturable absorber, a passively Q-switched Yb-doped fiber laser operating at 1062 nm is demonstrated. The maximum average output power of 3.49 mW is obtained with a minimum pulse width of 1.84 ps at a pulse repetition rate of 65.7 kHz, and the corresponding pulse energy and peak power are 53.1 nJ and 28.8 mW, respectively.展开更多
We report the repetitively Q-switched laser operation of the Yb-doped calcium niobium gallium garnet disordered garnet crystal, achieved with an acousto-optic modulator in a compact plano-concave resonator that is end...We report the repetitively Q-switched laser operation of the Yb-doped calcium niobium gallium garnet disordered garnet crystal, achieved with an acousto-optic modulator in a compact plano-concave resonator that is endpumped by a 935-nm diode laser. An average output power of 1.96 W is produced at pulse repetition rate of50 k Hz at emission wavelengths around 1035 nm, with a slope efficiency of 16%. The highest pulse energy of 269 μJ is generated at pulse repetition rate of 1 k Hz, with pulse width 12.1 ns and peak power 20.53 kW.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
We report on generation of a dual-wavelength, all-fiber, passively Q-switched ytterbium-doped fiber laser using aluminum oxide nanoparticle(Al_2 O_3-NP) thin flm. A thin film of Al_2 O_3 was prepared by embedding Al_2...We report on generation of a dual-wavelength, all-fiber, passively Q-switched ytterbium-doped fiber laser using aluminum oxide nanoparticle(Al_2 O_3-NP) thin flm. A thin film of Al_2 O_3 was prepared by embedding Al_2 O_3-NPs into a polyvinyl alcohol(PVA) as a host polymer, and then inserted between two fiber ferrules to act as a saturable absorber(SA).By incorporating the Al_2 O_3-PVA SA into the laser cavity,a stable dual-wavelength pulse output centered at 1050 and 1060.7 nm is observed at threshold pump power of 80 mW. As the pump power is gradually increased from 80 to 300 mW, the repetition rate of the generated pulse increases from 16.23 to 59 kHz, while the pulse width decreases from 19 to 6μs. To the best of our knowledge, this is the first demonstration for this type of SA operating in the 1 μm region.展开更多
In this work, the thermal characterization of continuously pumped passively Q-switched laser is quantitatively represented. The system under investigation is end-pumped Yb:YAG passively Q-switched by Cr4+:YAG as satur...In this work, the thermal characterization of continuously pumped passively Q-switched laser is quantitatively represented. The system under investigation is end-pumped Yb:YAG passively Q-switched by Cr4+:YAG as saturable absorber. The rate equations describing the dynamics of laser action are numerically solved simultaneously with the temperature conductivity heat equation to depict the transient temperature distribution. The study has been performed in the cylindrical coordinates to characterize the temperature distribution in the axial and radial directions. The thermal transient time in both directions as well as the thermal focal length are calculated. The temporal behavior of the temperature distribution has been illustrated in a 3-dimensional diagram.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
基金supported by the Natural Science Foundation of Anhui Province (Grant No. 2208085QF217)the National Natural Science Foundation of China (Grant No. 52102012)the Hefei Institutes of Physical Science (HFIPS) Director’s Fund (Grant No. YZJJ2022QN08)。
文摘We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.
基金support for this work through Grant, HiCoE (PRC-2022)the Universiti Malaya for the funding of this work through Grant Nos. RU005-2021 and MGO23-2022。
文摘We demonstrate antimonene as a saturable absorber(SA) to generate an ultrafast mode-locked and Q-switched laser in the 2 μm wavelength region. The two antimonene-based SAs were prepared and inserted separately in a thulium–holmiumdoped fiber laser to produce the pulsed laser. Antimonene was coated onto a tapered fiber to generate soliton mode-locked pulses and used in thin-film form for the generation of Q-switched pulses. The mode-locking was stable within a pump power of 267 m W–511 m W, and the laser operated at a central wavelength of 1897.4 nm. The mode-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 MHz, with a signal-to-noise ratio of 64 d B. Q-switched laser operation was stable at a wavelength of 1890.1 nm within a pump power of 312 m W–381 m W. With the increase in pump power from 312 m W to 381 m W, the repetition rate increased to a maximum of 56.63 k Hz and the pulse width decreased to a minimum value of 2.85 μs. Wide-range tunability of the Q-switched laser was also realized within the wavelength range of1882 nm–1936 nm.
基金Project supported by the Serving Local Special Project of Shaanxi Provincial Department of Education of China (Grant No. 19JC040)the National Natural Science Foundation of China (Grant No. 61905193)。
文摘We report a high repetition frequency, high power stability and low laser noise laser-diode(LD) end-pumped Nd: YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-polyvinyl alcohol(PVA) film as a saturable absorber(SA). A Brewster polarizer(BP) and a birefringent crystal(BC) are incorporated to enable frequency selection and filtering for the passively Q-switched 1123 nm pulsed laser to improve the power stability and reduce the noise. When the pump power is 5.1 W, an average output power of 457.9 m W is obtained, corresponding to a repetition frequency of 1.09 MHz,a pulse width of 56 ns, a spectral line width of 0.65 nm, a power instability of ±0.92%, and a laser noise of 0.89%.The successful implementation of the “Ti_(3)C_(2)T_(x)-PVA film passively Q-switching” combined with “frequency selection and filtering of BP + BC” technology path provides a valuable reference for developing pulsed laser with high repetition frequency, high stability and low noise.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61775053,51572053,51777046,and 61705140)
文摘We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 W were acquired from the Tm, Ho:LuVO4 laser with the pump power of 14.55 W, corresponding to a pulse width of 2.89 μs,a pulse repetition rate of 71.84 kHz, and a pulse energy of about 6.70 μJ.
基金Project supported by the National Natural Science Foundation of China(Grant No.61378024)
文摘A transmission-type tungsten disulfide(WS_2)-based saturable absorber(SA) is fabricated and applied to passively Q-switched Nd:YVO_4 laser.The WS_2 nanosheets are deposited on a quartz substrate by the vertical evaporation method.By inserting the WS2 SA into the plano-concave laser cavity,we achieve 153-ns pulses with an average output power of1.19 W at 1064 nm.To the best of our knowledge,both of them are the best results among those obtained by the Q-switched solid-state lasers with WS_2-based absorbers.The repetition rate ranges from 1.176 MHz to 1.578 MHz.As far as we know,it is the first time that MHz level Q-switched pulses have been generated in all solid state lasers based on low-dimensional materials so far.
基金Supported by the University of Malaya under Grant Nos PG173-2015B and PG004-2016A
文摘We demonstrate a passively Q-switched erbium-doped fiber laser(EDFL)using a copper nanoparticle(CuNP)thin film as the saturable absorber in a ring cavity.A stable Q-switched pulse operation is observed as the CuNP saturable absorber(SA)is introduced in the cavity.The pulse repetition rate of the EDFL is observed to be proportional to the pump power,and is limited to 101.2 kHz by the maximum pump power of 113.7 mW.On the other hand,the pulse width reduces from 10.19 ps to 4.28 ps as the pump power is varied from 26.1 mW to 113.7 mW.The findings suggest that CuNP SA could be useful as a potential saturable absorber for the development of the robust,compact,efficient and low cost Q-switched fiber laser operating at 1.5-μm region.
文摘In this paper, the effect of injected energy on low energy single longitudinal mode (SLM) pre-lase Q-switched is analyzed and the optimization procedure is shown in detail. Here, taking the Pr:YLF laser as an example of low energy laser, and the parameters of Pr:YLF laser by using pre-lase have been shown. Compared with normal Q-switched laser, the single pulse energy reaches 60.16% and the pulse width exceeds 39.73% when the same maximum energy is injected and SLM is achieved in pre-lase. The analysis results show that pre-lase is suitable for low energy laser to obtain SLM and there be an optimal performance to achieve the optimal energy output.
基金Project supported by the Science Fund from the Ministry of Higher Education of Malaysia(MOHE)(Grant No.FRGS/1/2016/STG02/UPM/02/5)
文摘A Q-switched erbium-doped fiber laser(EDFL)incorporating zinc-oxide(ZnO)nanoparticles-based saturable absorber(SA)is proposed and demonstrated.To form the SA,the ZnO nanoparticles,which are originally in the powder form,are first dissolved in ethanol and subsequently deposited onto the surface of fiber ferrule by using the adhesion effect with the evaporation technique.By integrating the ZnO nanoparticle-based SA into a laser cavity of an EDFL,a self-started and stable Q-switching is achieved at a low threshold power of 20.24 mW.As the pump power is increased,the pulse repetition rate is tunable from 10.34 kHz to 25.59 kHz while pulse duration decreases from 21.39μs to 3.65μs.Additionally,this Q-switched laser has a maximum energy per pulse of 19.34 nJ and an average output power of 0.46 mW.These results indicate the feasibility and functionality of the ZnO nanoparticles-based SA for Q-switched generation,which offers the flexibility and easy integration of the SA into a ring laser cavity.
基金Supported by West Young Scholar Foundation of the Chinese Academy of Sciences under Grant No XAB2015B27
文摘A black phosphorus(BP) saturable absorber(SA) solution with different concentrations(1.0 and 0.5 mg/ml) is fabricated with the liquid-phase exfoliation method. By using the BP-SA, a compact diode-pumped passively Q-switched Nd:YVO_4 laser is demonstrated. One reflecting Bragg gratings is used as the output coupler for mode selection. By inserting those BP-SA solutions in the laser cavity, the maximum single longitude mode,Q-switched output powers of 126 mW at 692.5 kHz and 149 mW at 630.3 kHz are achieved at the pump power of 8.0 W, corresponding to the pulse durations of 144 ns and 196 ns, respectively. Moreover, longitudinal-mode characteristics of Q-switched output laser in different optical cavity lengths based on two-kind BP-SA solution concentrations are investigated. Our results show that BP-SA could also be developed as an effective SA for the Q-switched, single longitudinal mode pulse laser.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574221)the Graduate Student’s Research and Innovation Fund of Sichuan University,China(Grant No.2018YJSY008).
文摘Fe^2+:ZnSe thin films are prepared on sapphire substrate at room temperature by electron beam evaporation and then annealed in vacuum(about 1×10^-4 Pa)at different temperatures.The influences of thermal annealing on the structural and optical properties of these films such as grain size and optical transmittance are investigated.The x-ray diffraction patterns show that the Fe2+:ZnSe thin film is preferred to be oriented along the(111)plane at different annealing temperatures.After the film is annealed,the full-width-at-half-maximum(FWHM)of the x-ray diffraction peak profile(111)of the film decreases and its crystal quality is improved.Scanning electron microscope images show that the films are more dense after being annealed.Finally,the sample is used as a saturable absorber in ZBLAN fiber laser.The annealed Fe^2+:ZnSe thin films can be used to realize stable Q-switching modulation on ZBLAN fiber laser.The results demonstrate that the Fe2+:ZnSe thin film is a promising material for generating the high-power pulses of mid-infrared Q-switched fiber lasers.
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.
基金Supported by the University of Malaya under Grant No PG173-2015B
文摘We demonstrate a Q-switched erbium-doped fiber laser(EDFL) using a newly developed zinc oxide-(ZnO) based saturable absorber(SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol)film. A small piece of the film is then sandwiched between two fiber ferrules and is incorporated in an EDFL cavity for generating a stable Q-switching pulse train. The EDFL operates at 1560.4 nm with a pump power threshold of 11.8 mW, a pulse repetition rate tunable from 22.79 to 61.43 kHz, and the smallest pulse width of 7.00 μs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 62 dB indicating the high stability of the laser. These results show that the ZnO powder has a great potential to be used for pulsed laser applications.
基金Supported by the National Natural Science Foundation of China under Grant No 61405046the Natural Science Foundation of Heilongjiang Province under Grant No 51305089
文摘A cw operation and a passively Q-switched(PQS) Ho:SSO laser(Cr^(2+):ZnSe as a saturable absorber) end-pumped by a Tm:YAP laser operating at near room temperature are reported. It is the first time to report a PQS Ho:SSO laser. For the cw mode, a maximum cw output power of 3.0 W is obtained, corresponding to a slope effciency of31.4%. For the PQS mode, a Cr^(2+):ZnSe is used as the saturable absorber, with transmission of 88.4% at 2112 nm.A maximum pulse energy of 1.29 mJ is obtained, corresponding to the pulse repetition frequency of 2.42 kHz. In this study, we change the distance between:Cr^(2+):ZnSe and the output mirror to research the pulse characteristic of the PQS Ho:SSO laser. The minimum pulse width of 73.5 ns is obtained, corresponding to the pulse energy of0.9 mJ and the pulse repetition frequency of 2.65 kHz.
文摘Background: Previously described methods for removal of tattoos are chemical, mechanical, surgical, termal and laser assited methods. Invention of the Q-switch mode, advanced the laser method, to be one of the most effective methods of tattoo removal. Objective: Comparing the tattoo removal and rate of lymphatic elimination of 3 different wavelengths of Q-switched Nd-YAG laser (532nm, 1064nm, combination 532 + 1064). Methods: In this study we examined lymphatic elimination and the effect of 532 nm, 1064 nm, and the combination (532 + 1064 nm) wavelength of laser pulse for the possible lymphatic cleansing mechanism of black pigmented tattoos. This study was performed on 18 New-Zealand rabbits, black pigmented tattoos were engraved on the back and the four extremities of the animals. 532 nm wavelength of Q switched Nd: YAG laser beam was applied on the left upper and bilateral lower extremities of the rabbits. During this period, excisional skin biopsies and lymph node biopsies were performed on days 7, 14 and 21. Results: Day 21 lymph node biopsies revealed mixed type of reactive hyperplasia and intracellular pigments were markedly seen in the laser treatment group and no intracellular tattoo pigment was seen in the control group. Conclusion: The findingd of this study indicate that lymphatic elimination may be one of the significant mechanisms of tattoo removal and the application of different wavelengths of Q-switched Nd-YAG laser do not show statistically significant differences in tattoo removal.
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A two-dimensional silver nanoplate is prepared with the seed-mediated growth method and is used for achieving pulse fiber laser operation. By controlling the dimension parameters of the silver nanoplate, the surface plasmon resonance absorption peak of the material is successfully adjusted to 1068 nm. Based on the silver nanoplate as a saturable absorber, a passively Q-switched Yb-doped fiber laser operating at 1062 nm is demonstrated. The maximum average output power of 3.49 mW is obtained with a minimum pulse width of 1.84 ps at a pulse repetition rate of 65.7 kHz, and the corresponding pulse energy and peak power are 53.1 nJ and 28.8 mW, respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274188 and 11574170
文摘We report the repetitively Q-switched laser operation of the Yb-doped calcium niobium gallium garnet disordered garnet crystal, achieved with an acousto-optic modulator in a compact plano-concave resonator that is endpumped by a 935-nm diode laser. An average output power of 1.96 W is produced at pulse repetition rate of50 k Hz at emission wavelengths around 1035 nm, with a slope efficiency of 16%. The highest pulse energy of 269 μJ is generated at pulse repetition rate of 1 k Hz, with pulse width 12.1 ns and peak power 20.53 kW.
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.
基金Supported by the Iraqi Ministry of Higher Education and Scientific Research and University of Baghdad
文摘We report on generation of a dual-wavelength, all-fiber, passively Q-switched ytterbium-doped fiber laser using aluminum oxide nanoparticle(Al_2 O_3-NP) thin flm. A thin film of Al_2 O_3 was prepared by embedding Al_2 O_3-NPs into a polyvinyl alcohol(PVA) as a host polymer, and then inserted between two fiber ferrules to act as a saturable absorber(SA).By incorporating the Al_2 O_3-PVA SA into the laser cavity,a stable dual-wavelength pulse output centered at 1050 and 1060.7 nm is observed at threshold pump power of 80 mW. As the pump power is gradually increased from 80 to 300 mW, the repetition rate of the generated pulse increases from 16.23 to 59 kHz, while the pulse width decreases from 19 to 6μs. To the best of our knowledge, this is the first demonstration for this type of SA operating in the 1 μm region.
文摘In this work, the thermal characterization of continuously pumped passively Q-switched laser is quantitatively represented. The system under investigation is end-pumped Yb:YAG passively Q-switched by Cr4+:YAG as saturable absorber. The rate equations describing the dynamics of laser action are numerically solved simultaneously with the temperature conductivity heat equation to depict the transient temperature distribution. The study has been performed in the cylindrical coordinates to characterize the temperature distribution in the axial and radial directions. The thermal transient time in both directions as well as the thermal focal length are calculated. The temporal behavior of the temperature distribution has been illustrated in a 3-dimensional diagram.
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.
