High power solid state laser operating in continuous / pulse composite mode
Lei Liu, Wentao Wang, Chao Wang, Gang Wang, Yang Liu, Youquan Jia, Ning Li, Kunpeng Lv, and Lu Chen
Conventional high-power lasers operate in either continuous wave or long pulse mode. They interact with materials mainly through heating, whose effects are very limited when working with complex targets. We propose a novel high-power laser technology based on the combinations of continuous and pulse lasers with adjustable pulse widths and repetition frequencies. Such a “heating/shock” function can be used to improve the effect of high-power laser by aiming the best time-domain eigenvalues of melting and gasification of various target materials. We have achieved output power of 4800 W with 3600 W from continuous wave operation and 1200 W from pulsed operation with repetition rate of 10 kHz and pulse width of 3.6 ns. When the repetition rate is increased to 100 Hz, the resultant output power of the 7 ns pulsed laser is 1820 W, while the power of the continuous laser is 3100 W, and the beam quality is 4.8 times of the diffraction limit.Conventional high-power lasers operate in either continuous wave or long pulse mode. They interact with materials mainly through heating, whose effects are very limited when working with complex targets. We propose a novel high-power laser technology based on the combinations of continuous and pulse lasers with adjustable pulse widths and repetition frequencies. Such a “heating/shock” function can be used to improve the effect of high-power laser by aiming the best time-domain eigenvalues of melting and gasification of various target materials. We have achieved output power of 4800 W with 3600 W from continuous wave operation and 1200 W from pulsed operation with repetition rate of 10 kHz and pulse width of 3.6 ns. When the repetition rate is increased to 100 Hz, the resultant output power of the 7 ns pulsed laser is 1820 W, while the power of the continuous laser is 3100 W, and the beam quality is 4.8 times of the diffraction limit.
- Mar. 15, 2022
- High Power Laser and Particle Beams
- Vol. 34, Issue 3, 031007 (2022)
- DOI：10.11884/HPLPB202234.210292
Analysis on performance of two-photon Rb vapor laser
Yanhui Ji, Yang He, Guochao Lao, Haohua Wan, and Fei Chen
Two-photon absorbing alkali vapor laser (TPAL) has important application prospects in basic research and defense engineering, and has become one of the research hotspots in the laser field in recent years. However, TPAL still lacks relevant theoretical models. The operating characteristics of a single-wavelength pumped two-photon absorbing rubidium vapor laser (Rb-TPAL) are investigated, and the effects of pump beam waist position, vapor cell temperature and pump power on the blue light output characteristics of Rb-TPAL are analyzed. The results show that the optimal pump beam waist position and vapor cell temperature exist for the Rb-TPAL to output the highest power blue laser. By optimizing the pump beam waist position and vapor cell temperature, the Rb-TPAL can obtain high power blue laser output under high power pumping.Two-photon absorbing alkali vapor laser (TPAL) has important application prospects in basic research and defense engineering, and has become one of the research hotspots in the laser field in recent years. However, TPAL still lacks relevant theoretical models. The operating characteristics of a single-wavelength pumped two-photon absorbing rubidium vapor laser (Rb-TPAL) are investigated, and the effects of pump beam waist position, vapor cell temperature and pump power on the blue light output characteristics of Rb-TPAL are analyzed. The results show that the optimal pump beam waist position and vapor cell temperature exist for the Rb-TPAL to output the highest power blue laser. By optimizing the pump beam waist position and vapor cell temperature, the Rb-TPAL can obtain high power blue laser output under high power pumping.
- Mar. 15, 2022
- High Power Laser and Particle Beams
- Vol. 34, Issue 3, 031006 (2022)
- DOI：10.11884/HPLPB202234.210290
Research on bonding test of 5052 aluminum alloy based on laser texturing technology
Yanlong Xu, Wenge Li, Zhonghan Yu, Yuantao Zhao, Feng Gao, and Xilian Xie
To improve the bonding performance of 5052 aluminum alloy, the laser texturing experiment on aluminum alloy specimens was carried out by using the short pulse and high peak power characteristics of pulsed fiber laser. Through the orthogonal experiment method, the effects of process parameters such as the average power, scanning speed, pulse frequency, pulse width and other parameters on the quality of laser texturing, as well as the influence weight of each process parameter, and the best process parameters are obtained. The best process parameters are average power 90 W, scanning speed 10mm/s, pulse frequency 1000 kHz, and pulse width 200 ns. According to the optimized parameters, a good area with roughness 2.35 μm is obtained. Then a single-lap tensile test on the aluminum alloy specimens after laser texturing was carried out. The study found that the bonding strength would increase with the increase of roughness, when the roughness reached a certain level, the bonding strength would decrease with the increase of roughness. In addition, the bonding strength is also closely related to the type and density of the microtexture on the surface of the aluminum alloy.To improve the bonding performance of 5052 aluminum alloy, the laser texturing experiment on aluminum alloy specimens was carried out by using the short pulse and high peak power characteristics of pulsed fiber laser. Through the orthogonal experiment method, the effects of process parameters such as the average power, scanning speed, pulse frequency, pulse width and other parameters on the quality of laser texturing, as well as the influence weight of each process parameter, and the best process parameters are obtained. The best process parameters are average power 90 W, scanning speed 10mm/s, pulse frequency 1000 kHz, and pulse width 200 ns. According to the optimized parameters, a good area with roughness 2.35 μm is obtained. Then a single-lap tensile test on the aluminum alloy specimens after laser texturing was carried out. The study found that the bonding strength would increase with the increase of roughness, when the roughness reached a certain level, the bonding strength would decrease with the increase of roughness. In addition, the bonding strength is also closely related to the type and density of the microtexture on the surface of the aluminum alloy.
- Mar. 15, 2022
- High Power Laser and Particle Beams
- Vol. 34, Issue 3, 031010 (2022)
- DOI：10.11884/HPLPB202234.210283
Experimental study on high brightness blue diode laser fiber coupling
Hao Tan, Hualing Wu, Quanwei Jiang, Lanping Zhang, Linhui Guo, Bo Fu, and Songxin Gao
Based on the advantages of diode laser, such as high efficiency and high integration, blue diode laser source can be widely used in highly-reflective and highly conductive materials processing. This paper introduces a high power high brightness blue diode laser fiber coupling module based on 3×9 single emitter diode laser array, which can realize 75 W single polarization 450 nm diode laser output from 100 μm 0.2 NA fiber. Polarization beam combining can also be used to further improve the fiber coupling blue diode laser power.Based on the advantages of diode laser, such as high efficiency and high integration, blue diode laser source can be widely used in highly-reflective and highly conductive materials processing. This paper introduces a high power high brightness blue diode laser fiber coupling module based on 3×9 single emitter diode laser array, which can realize 75 W single polarization 450 nm diode laser output from 100 μm 0.2 NA fiber. Polarization beam combining can also be used to further improve the fiber coupling blue diode laser power.
- Mar. 15, 2022
- High Power Laser and Particle Beams
- Vol. 34, Issue 3, 031009 (2022)
- DOI：10.11884/HPLPB202234.210274
Stable 33W average green light obtained with KTP crystaI as intraca vity frequency-doubler
Huang Chaoen, Han Pengdi, Chen Denjin, Liu Youchen, and Liu Wei
6.5 W CW green light has been achieved in a Nd:YAG laser by using KTP crystal grown by an improved fiux technique in our institute as intracavity irequency-doubler. An average output oi 33 W at 532 nm has been demonstrated when an acousto-optical Q-switch operating at 25 kHz was used. The stability of KTP doubler was also checked.6.5 W CW green light has been achieved in a Nd:YAG laser by using KTP crystal grown by an improved fiux technique in our institute as intracavity irequency-doubler. An average output oi 33 W at 532 nm has been demonstrated when an acousto-optical Q-switch operating at 25 kHz was used. The stability of KTP doubler was also checked.
- Jan. 01, 1900
- Chinese Journal of Lasers
- Vol. 15, Issue 10, 586 (1988)
- DOI：
Dual-Wavelength Fiber Laser Based on Er3+-Doped Superimposed Fiber Gratings
Wang Feng, Bi Weihong, Fu Xinghu, Jiang Peng, and Wu Yang
Based on gain homogeneity technology, a new type of dual-wavelength fiber laser is proposed and demonstrated. Linear cavity structure is used in the fiber laser, two Er3+-doped superimposed fiber gratings with reflectivity above 99% are used for wavelength selection, and Er3+-doped fiber is used as the gain medium. The experimental results show that precise adjustment of the mechanical stress at two ends of the superimposed fiber gratings can regulate the reflectivity (or transmissivity) of cavity lenses at the output end at wavelengths of λ1 and λ2, i.e. regulate the laser loss, which makes the gain and loss at two wavelengths in the resonance cavity match well, inhibits mode competition in the resonance cavity, and achieves stable simultaneous dual-wavelength laser emission with wavelength interval of 0.932 nm. The threshold power of the proposed laser is 4 mW, the 3 dB band width is 0.02 nm, the 30 dB band width is less than 0.2 nm, and the side mode suppression ratio is 51.96 dB. This laser have such advantages as simple structure, stable output at room temperature, narrow band width and low threshold.Based on gain homogeneity technology, a new type of dual-wavelength fiber laser is proposed and demonstrated. Linear cavity structure is used in the fiber laser, two Er3+-doped superimposed fiber gratings with reflectivity above 99% are used for wavelength selection, and Er3+-doped fiber is used as the gain medium. The experimental results show that precise adjustment of the mechanical stress at two ends of the superimposed fiber gratings can regulate the reflectivity (or transmissivity) of cavity lenses at the output end at wavelengths of λ1 and λ2, i.e. regulate the laser loss, which makes the gain and loss at two wavelengths in the resonance cavity match well, inhibits mode competition in the resonance cavity, and achieves stable simultaneous dual-wavelength laser emission with wavelength interval of 0.932 nm. The threshold power of the proposed laser is 4 mW, the 3 dB band width is 0.02 nm, the 30 dB band width is less than 0.2 nm, and the side mode suppression ratio is 51.96 dB. This laser have such advantages as simple structure, stable output at room temperature, narrow band width and low threshold.
- Jan. 01, 1900
- Chinese Journal of Lasers
- Vol. 43, Issue 4, 402002 (2016)
- DOI：10.3788/cjl201643.0402002
Gain-Switched Semiconductor Pulsed Laser for Quantum Secure Communication
Zhou Qiang, Liu Jinlu, Gu Yuanhui, Fan Fan, Wang Yunxiang, and Xu Bingjie
In the last three decades, quantum information science and technology is one of the most exciting research fields. Among all the achievements, quantum secure communication technology is gradually started from experimental research to engineering application and expected to take the lead in achieving the commercial development. Towards the comprehensive popularization of the quantum secure communication system, a picosecond pulsed laser module has been designed and fabricated based on the gain-switching effect of the semiconductor laser and commercial electronic chips. The realized laser module has the following properties: operating wavelength at the low transmission loss window of fiber quantum channel, i.e., 1.5 μm; with a frequency fluctuation of less than 20 MHz; pulse time domain width of tens of picoseconds; no fixed phase correlation between any two pulses. Moreover, these properties are verified and discussed based on the requirement of weak coherent single photon source for quantum secure communication application.In the last three decades, quantum information science and technology is one of the most exciting research fields. Among all the achievements, quantum secure communication technology is gradually started from experimental research to engineering application and expected to take the lead in achieving the commercial development. Towards the comprehensive popularization of the quantum secure communication system, a picosecond pulsed laser module has been designed and fabricated based on the gain-switching effect of the semiconductor laser and commercial electronic chips. The realized laser module has the following properties: operating wavelength at the low transmission loss window of fiber quantum channel, i.e., 1.5 μm; with a frequency fluctuation of less than 20 MHz; pulse time domain width of tens of picoseconds; no fixed phase correlation between any two pulses. Moreover, these properties are verified and discussed based on the requirement of weak coherent single photon source for quantum secure communication application.
- Jan. 01, 1900
- Chinese Journal of Lasers
- Vol. 43, Issue 5, 502005 (2016)
- DOI：10.3788/cjl201643.0502005
Effects of Linewidth of Seed-Laser on Output Features of End-Pumped Alkali Vapor Amplifier
Jiang Zhigang, Wang You, Han Juhong, Cai He, Gao Ming, An Guofei, Xue Liangping, Zhang Wei, Wang Hongyuan, and Zhou Jie
In recent years, the diode pumped alkali laser (DPAL) has been rapidly developed as a new laser source. The master oscillator power-amplifier (MOPA) system is one of the most feasible engineering methods to achieve the high power scaling of DPAL. Comparing with traditional lasers, DPAL′s linewidths of both absorption and emission are extremely narrow. Therefore, the linewidth of a seed laser is one of the most important factors that effects the output characteristics of DPAL-MOPA. A theoretical microcosmic kinetic mode is established for an end-pumped DPAL-MOPA system. The linewidth of seed laser and the spectral distribution of emission cross-section are taken into account in the calculation process. The influences of linewidth of seed laser on the features, including the output power, output linewidth, extraction efficiency, gain factor, and pump absorption, are calculated and analyzed in detail. The research is helpful in construction of a power-scaled DPAL-MOPA system.In recent years, the diode pumped alkali laser (DPAL) has been rapidly developed as a new laser source. The master oscillator power-amplifier (MOPA) system is one of the most feasible engineering methods to achieve the high power scaling of DPAL. Comparing with traditional lasers, DPAL′s linewidths of both absorption and emission are extremely narrow. Therefore, the linewidth of a seed laser is one of the most important factors that effects the output characteristics of DPAL-MOPA. A theoretical microcosmic kinetic mode is established for an end-pumped DPAL-MOPA system. The linewidth of seed laser and the spectral distribution of emission cross-section are taken into account in the calculation process. The influences of linewidth of seed laser on the features, including the output power, output linewidth, extraction efficiency, gain factor, and pump absorption, are calculated and analyzed in detail. The research is helpful in construction of a power-scaled DPAL-MOPA system.
- Jan. 01, 1900
- Chinese Journal of Lasers
- Vol. 43, Issue 5, 502004 (2016)
- DOI：10.3788/cjl201643.0502004
Study on a Non-Chain Discharge-Pumped Pulse Deuterium Fluoride Lasers
You Libing, Yin Guangyue, Wang Qinsheng, and Fang Xiaodong
The compact non-chain discharge-pumped pulse deuterium fluoride (DF) laser is studied, the discharge trigger circuit is introduced based on one-stage thyratron magnetic pulse with fast rise time. Discharging voltage of 39.5 kV and pulse rise time of 100 ns are achieved. With the condition of 190 J/L energy depositions, a uniform glow discharge is formed using compact Chang-electrode combined with ultraviolet (UV) spark pre-ionization, and the distance between the cathode and anode is 30 mm. With flat-flat cavity laser resonators, mixture gas of SF6and D2is investigated. By optimizing the gas ratio to 10:3, the laser pulse energy is up to 877 mJ. The electro-optic conversion efficiency is about 1.9% and the pulse width is 200 ns with the beam dimensions of 30 mm×9 mm.The compact non-chain discharge-pumped pulse deuterium fluoride (DF) laser is studied, the discharge trigger circuit is introduced based on one-stage thyratron magnetic pulse with fast rise time. Discharging voltage of 39.5 kV and pulse rise time of 100 ns are achieved. With the condition of 190 J/L energy depositions, a uniform glow discharge is formed using compact Chang-electrode combined with ultraviolet (UV) spark pre-ionization, and the distance between the cathode and anode is 30 mm. With flat-flat cavity laser resonators, mixture gas of SF6and D2is investigated. By optimizing the gas ratio to 10:3, the laser pulse energy is up to 877 mJ. The electro-optic conversion efficiency is about 1.9% and the pulse width is 200 ns with the beam dimensions of 30 mm×9 mm.
- Jan. 01, 1900
- Chinese Journal of Lasers
- Vol. 43, Issue 5, 502003 (2016)
- DOI：10.3788/cjl201643.0502003
Laser Diode Pumped 4.1 kW All-Fiber Laser with Master Oscillator Power Amplification Configuration
Wang Xiaolin, Zhang Hanwei, Tao Rumao, Su Rongtao, Zhou Pu, and Xu Xiaojun
A laser diode (LD) pumped all-fiber laser with master oscillator power amplification configuration is demonstrated, of which output power is more than 4 kW. The stimulated Raman scattering (SRS) and transverse mode instability (TMI) charateristics of lasers are experimentally studied under different core-diameter gain fibers and different pump wavelengths. In order to mitigate SRS, a large mode area Yb3+ doped fiber with core diameter of 30 μm is selected as gain media. In order to suppress TMI, LD with center wavelength of 915 nm is used as pump source, so the absorption coefficient of the gain fiber is lower at 915 nm, and the bending radius of the gain fiber is reduced to 10 cm to increase the loss of the higher modes. When the seed power is 100 W, the highest pump power is 5.3 kW, the laser power of 4.1 kW is achieved, and the beam quality M2 is 2.2. There are no SRS and TMI effects observed in the output laser.A laser diode (LD) pumped all-fiber laser with master oscillator power amplification configuration is demonstrated, of which output power is more than 4 kW. The stimulated Raman scattering (SRS) and transverse mode instability (TMI) charateristics of lasers are experimentally studied under different core-diameter gain fibers and different pump wavelengths. In order to mitigate SRS, a large mode area Yb3+ doped fiber with core diameter of 30 μm is selected as gain media. In order to suppress TMI, LD with center wavelength of 915 nm is used as pump source, so the absorption coefficient of the gain fiber is lower at 915 nm, and the bending radius of the gain fiber is reduced to 10 cm to increase the loss of the higher modes. When the seed power is 100 W, the highest pump power is 5.3 kW, the laser power of 4.1 kW is achieved, and the beam quality M2 is 2.2. There are no SRS and TMI effects observed in the output laser.
- Jan. 01, 1900
- Chinese Journal of Lasers
- Vol. 43, Issue 5, 502002 (2016)
- DOI：10.3788/cjl201643.0502002
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