- Email: [email protected]
Cr4+:YAG composite crystal
Accepted Manuscript Title: High-repetition-rate, high-peak-power burst mode laser with YAG/Nd:YAG/Cr4+ :YAG composite crystal Authors: Renpeng Yan, Xudong Li, Yinbo Zhang, Zhixiang Liu, Xiaolin Wen, Deying Chen, Zhongxiang Zhou PII: DOI: Reference:
S0030-4026(18)31311-1 https://doi.org/10.1016/j.ijleo.2018.09.016 IJLEO 61455
To appear in: Received date: Accepted date:
1-7-2018 6-9-2018
Please cite this article as: Yan R, Li X, Zhang Y, Liu Z, Wen X, Chen D, Zhou Z, High-repetition-rate, high-peak-power burst mode laser with YAG/Nd:YAG/Cr4+ :YAG composite crystal, Optik (2018), https://doi.org/10.1016/j.ijleo.2018.09.016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
High-repetition-rate, high-peak-power burst mode laser with YAG/Nd:YAG/Cr4+:YAG composite crystal
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Renpeng Yana,b*, Xudong Lia,b, Yinbo Zhangb, Zhixiang Liuc, Xiaolin Wenc, Deying Chenb, Zhongxiang Zhoua
a
c
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Post-doctoral Mobile Station of Physics, Department of Physics, Harbin Institute of Technology, Harbin 150001, China b National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150080, China Shenzhen Aerospace Industry Technology Research Institute, Shenzhen 518000, China
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author’s email: [email protected]
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*coresponding
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Abstract: A high-repetition-rate, high-peak-power 808 nm LD pumped burst mode 1064 nm laser is demonstrated with a YAG/Nd:YAG/Cr4+:YAG composite crystal. A pulse burst energy of 13.2 mJ in a duration of 1 ms is obtained at 31.1 kHz with an optical-to-optical efficiency of 27.2% and a single pulse energy of 425.8 μJ. The pulse width keeps nearly invariable during the pump region and the shortest pulse width is 1.9 ns. The peak power of pulse burst laser reaches 373.7 kW at 10.2 kHz. The beam quality factors of pulse burst laser at 31.1 kHz are measured to be Mx2=1.5 and My2 =1.7 by using the travelling knife-edge method.
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Key words: burst mode, passively Q-switching, composite crystal.
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1. Introduction High-repetition-rate, high-peak-power pulsed laser sources play important roles in laser processing, LiDAR and laser diagnostics. Diode pumped solid-state laser (DPSSL) has advantages of compactness, high-efficiency, and long lifetime [1-3]. DPSSLs are capable to generate pulsed lasers at high-repetition rate, but the average power is restricted to a low level due to thermal effects. Pulse burst technique is a promising approach to provide a series of high energy pulses at high repetition rate in a short time duration [4-6]. It is especially useful for applications in laser diagnostic of turbulent flow fields characterized by turbulent time in the order of microseconds. In recent years, pulse burst laser with laser diode (LD) side-pumped amplifiers have been developed
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and utilized in laser-based diagnostics [7-9]. Composite laser rod with un-doped cap and saturable absorber is effective approach to get compact pulsed laser at high repetition rate [10, 11]. In previous study, a directly-pumped YAG/Nd:YAG/Cr4+:YAG pulse burst laser is reported with a single pulse energy of 210 μJ and a repetition rate of 11 kHz [12]. But the repetition and efficiency is limited due to the low absorption efficiency. In this paper, we present a high-repetition-rate, high-peak-power burst mode 1064 nm laser with a YAG/Nd:YAG/Cr4+:YAG composite crystal pumped by an 808 nm LD. The output laser performances with different pump beam radii are compared. With a pump radius of ωp=240 μm, the pulse burst energy of 13.2 mJ is obtained at 31.1 kHz, corresponding to an optical-to-optical efficiency of 27.2% and a single pulse energy of 425.8 μJ. The pulse width keeps nearly invariable during the pump region and the shortest pulse width is 1.9 ns. The beam quality factors are calculated to be Mx2=1.5 and My2 =1.7 by using the travelling knife-edge method. The maximum single pulse energy of 710 μJ is obtained at 10.2 kHz with a peak power of 373.7 kW.
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2. Experimental setup
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The experimental setup of 808 nm LD pumped burst mode laser with a YAG/Nd:YAG/Cr4+:YAG composite crystal is shown in Fig.1. The pump source is a fiber coupled LD at 808 nm with a maximum power of 50 W. The fiber diameter is 400 μm and the numerical aperture (N.A.) is 0.22. The pump duration is set at 1ms, long enough for high-speed turbulent flow diagnostic and the repetition rate is 100 Hz. The pump beam is re-imaged into laser rod by coupling systems with different coupling ratios. A composite YAG/Nd:YAG/Cr4+:YAG crystal serves as laser medium and Qswitch with a dimension of (2+5.5+1.5)×3×3 mm3. Both end faces are coated with high transmission at 1064 nm and 808 nm. The doping concentration of Nd:YAG is 1.0at.% and the initial transmission of Cr4+:YAG saturable absorber is T0=40% at 1064 nm. The rod is wrapped with indium folder, mounted in heat sink and kept at 20 ℃ by water cooling. The laser resonator is composed with two plane mirrors and the transmission of output coupler is T=40% at 1064 nm. The geometric length of laser cavity is 25 mm. The pulse characters of pulse burst laser are measured by a photodiode (DET10A, Thorlabs Inc.) and recorded by a digital oscilloscope (DSO-X 3034A, Agilent Technologies Inc.).
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3. Experimental results and discussions The output wavelength of LD is measured to be around 807 nm with a full width at half maximum (FWHM) of 1.5 nm. The absorption efficiency of Nd:YAG is estimated to be 70%. Output pulse energy of 808 nm LD pumped YAG/Nd:YAG/Cr4+:YAG pulse burst laser with different pump beam radii is investigated, as shown in Fig. 2. The pulse burst energy increase linearly with incident pump energy and the maximum efficiency is achieved with a pump beam radius of ωp=240 μm. At the incident pump energy of 48.5 mJ, the maximum energy reaches 13.2 mJ with an optical-to-optical efficiency of 27.2%. The threshold pump power with a pump beam radius of ωp=166μm is lowest
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due to high pump density, but the laser efficiency is reduced at higher pump energy because of lower overlap efficiency. The maximum output burst energies are 11.2 mJ and 7.1 mJ respectively when the pump beam radii are ωp=380 μm and ωp=166 μm. Figure 3 presents pulse repetition rate of pulse burst laser versus incident pump energy. The pulse repetition rate and pulse number in a burst increase with pump power. With a pump beam radius of ωp=166 μm, a repetition rate of 67.4 kHz is obtained, which is higher than 31.1 kHz and 10.2 kHz with pump beam radii of ωp=240μm and ωp=380μm. There are 67 pulses in the pulse burst duration of 1 ms with a single pulse energy of 171 μJ. The highest single pulse energy of 710 μJ is achieved at 10.2 kHz with a pump beam radius of ωp=380 μm. The temporal pulse train of 31.1 kHz is given in Fig. 4 and no pulse lost is observed. The variation of pulse width as the function of incident pump energy is given in Fig. 5. It could be seen that the pulse width keeps nearly constant around 2 ns within the whole pump region. It could be ascribed to the changeless value of the modulation depth during passively Q-switching operation [13]. The shortest pulse width of 1.9 ns is obtained with a pump beam radius of ωp=240 μm. The temporal pulse profile of 1.9 ns is illustrated in Fig. 6, which has a sharp rising edge. The maximum peak power is calculated to be 373.7 kW at 10.2 kHz in the pulse burst laser. The peak powers reach 72.8 kW at 67.4 kHz and 212.9 kW at 31.1 kHz. The beam density distribution of pulse burst laser at 31.1 kHz is measured by a laser beam analyzer (LBA-712PC-D, Spiricon Inc.), as shown in Fig. 7. It shows good symmetry in both directions. By using the travelling knife-edge method [14], the beam radius variation of pulse burst laser at 31.1 kHz is measured, as given in Fig. 8. The beam quality factors are calculated to be Mx2=1.5 and My2 =1.7 by fitting these data to Gaussian beam propagation expression.
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4. Conclusions
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In conclusion, we presented a high-repetition-rate, high-peak-power LD pumped burst mode 1064 nm laser with a YAG/Nd:YAG/Cr4+:YAG composite crystal. The output laser performances with different pump beam radii are investigated. When the pump radius is ωp=240 μm, the pulse burst energy at 1064 nm reaches 13.2 mJ with an opticalto-optical efficiency of 27.2% and a single pulse energy of 425.8 μJ. The maximum repetition rate of 67.4 kHz is achieved with a pump beam radius of ωp=166 μm. The pulse width keeps nearly invariable during the pump region and the shortest pulse width reaches 1.9 ns. The maximum single pulse energy of 710 μJ is obtained at 10.2 kHz with a peak power of 373.7 kW by using a pump beam radius of ωp=380 μm. By using the travelling knife-edge method, the beam quality factors at 31.1 kHz are measured to be Mx2=1.5 and My2 =1.7. The pulse energy would be further amplified to satisfied the requirement in laser based diagnostics. Acknowledgements This work was supported by the National Natural Science Foundation of China (NSFC) (61605032 and 61505042), Shenzhen Science and Technology Program (JSGG20170414141239041), General Financial Grant from the China Postdoctoral
Science Foundation (Grant No. 2015M80263), the Fundamental Research Funds for Central Universities (Grant No. HIT. NSRIF. 2017018).
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References 1. G. Huber, C. Kränkel, K. Petermann, Solid-state lasers: status and future, J. Opt. Soc. Am. B, 27(11) (2010), B93-B105. 2. T. Y. Fan and R. L. Byer, Modeling and cw operation of a quasi-three-level 946 nm Nd:YAG laser, IEEE J. Quantum. Electron. 23 (1987), 605-612. 3. X. Fu, Q. Liu, X. Yan, J. Cui, and M. Gong, 120 W high repetition rate Nd:YVO4 MOPA laser with a Nd:YAG cavity-dumped seed laser, Appl. Phys. B. 95 (2009), 63-67. 4. B. Thurow, N. Jiang, W. Lempert, Review of ultra-high repetition rate laser diagnostics for fluid dynamic measurements, Meas. Sic. Technol., 24 (2013) 012002. 5. B. Thurow, A. Satija, K. Lynch, Third-generation megahertz-rate pulse burst laser system, Appl. Opt. 48(11) (2009), 2086-2093. 6. M. Slipchenko, J. Miller, S. Roy, J. Gord, T. Meyer, All-diode-pumped quasicontinuous burst-mode laser for extended high-speed planar imaging, Opt. Express, 21(1) (2013), 681-689. 7. P. Wu, W. Lempert, and R. Miles, Megahertz pulse-burst laser and visualization of shock-wave/ boundary-layer interaction, J. AIAA, 38(4) (2000), 672-679. 8. J. Miller, S. Engel, J. Troger, Characterization of a CH planar laser-induced fluorescence imaging system using a kHz-rate multimode-pumped optical parametric oscillator, Appl. Opt. 51(14) (2012), 2589-2600. 9. R. Pan, U. Retzer, T. Werblinski, M. Slipchenko, T. Meyer, L. Zigan, S. Will, Generation of high-energy, kilohertz-rate narrowband tunable ultraviolet pulses using a burst-mode dye laser system, Opt. Lett. 43(5) (2018) 1191-1194. 10. W. Jiang, Y. Liu, W. Chen, S. Zhu, Z. Chen, G. Zhang, Y. Chen, Z. Chen, Composite Yb:YAG/Cr4+:YAG/YAG crystal passively Q-switched lasers at 1030 nm, Appl. Opt. 54(7) (2015) 1834-1838. 11. Q. Zhou, S. Zhu, W. Jiang, Z. Li, Y. Wang, H. Yin, Z. Chen, J. Yuan, Diode-endpumped passively Q-switched blue laser with Nd:YAG/YAG/Cr4+:YAG/YAG composite crystal, Optik, 127 (2016) 10588-10592. 12. X. Li, Y. Zhou, R. Yan, D. Wang, X. Fa, Y. Ma, Z. Zhou, A compact pulse burst laser with YAG/Nd:YAG/Cr4+:YAG composite crystal, Optik, 136 (2017) 107-111. 13. R. Yan, X. Yu, Y. Ma, X. Li, D. Chen and J. Yu, High-peak-power, short-pulsewidth, LD end-pumped, passively Q-switched Nd:YAG 946 nm laser, Opt. Commun., 285 (2012), 4462-4465.
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14. J. M. Khosrofian and B. A. Garetz, Measurement of a Gaussian laser beam diameter through the direct inversion of knife-edge data, Appl. Opt. 22(21) (1983), 34063410.
Figure captions
Laser Diode
Coupling Optics
Fiber
M1
M2 YAG+Nd:YAG+Cr:YAG Laser output
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Figure 1. Experimental setup 15
wp=240mm
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wp=380mm
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Fig. 2. Output pulse burst energy versus incident pump burst energy with different pump radii
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Pulse repetition rate (kHz)
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Fig. 3. Pulse repetition rate versus incident pump energy with different pump radii
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Fig. 4. Temporal pulse train of pulse burst laser at 31.1 kHz
Incident pump energy (mJ)
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Fig. 5. Variation of pulse width versus incident pump energy with different pump radii 10
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Intensity (a.u.)
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1.9 ns
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Fig. 6. Temporal pulse profile of 1.9 ns
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My2=1.7
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Fig. 8. Beam radius variation of pulse burst laser at 31.1 kHz
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Fig. 7. The laser density distribution of pulse burst laser
S0030-4026(18)31311-1 https://doi.org/10.1016/j.ijleo.2018.09.016 IJLEO 61455
To appear in: Received date: Accepted date:
1-7-2018 6-9-2018
Please cite this article as: Yan R, Li X, Zhang Y, Liu Z, Wen X, Chen D, Zhou Z, High-repetition-rate, high-peak-power burst mode laser with YAG/Nd:YAG/Cr4+ :YAG composite crystal, Optik (2018), https://doi.org/10.1016/j.ijleo.2018.09.016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
High-repetition-rate, high-peak-power burst mode laser with YAG/Nd:YAG/Cr4+:YAG composite crystal
IP T
Renpeng Yana,b*, Xudong Lia,b, Yinbo Zhangb, Zhixiang Liuc, Xiaolin Wenc, Deying Chenb, Zhongxiang Zhoua
a
c
SC R
Post-doctoral Mobile Station of Physics, Department of Physics, Harbin Institute of Technology, Harbin 150001, China b National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150080, China Shenzhen Aerospace Industry Technology Research Institute, Shenzhen 518000, China
U
author’s email: [email protected]
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*coresponding
PT
ED
M
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Abstract: A high-repetition-rate, high-peak-power 808 nm LD pumped burst mode 1064 nm laser is demonstrated with a YAG/Nd:YAG/Cr4+:YAG composite crystal. A pulse burst energy of 13.2 mJ in a duration of 1 ms is obtained at 31.1 kHz with an optical-to-optical efficiency of 27.2% and a single pulse energy of 425.8 μJ. The pulse width keeps nearly invariable during the pump region and the shortest pulse width is 1.9 ns. The peak power of pulse burst laser reaches 373.7 kW at 10.2 kHz. The beam quality factors of pulse burst laser at 31.1 kHz are measured to be Mx2=1.5 and My2 =1.7 by using the travelling knife-edge method.
CC E
Key words: burst mode, passively Q-switching, composite crystal.
A
1. Introduction High-repetition-rate, high-peak-power pulsed laser sources play important roles in laser processing, LiDAR and laser diagnostics. Diode pumped solid-state laser (DPSSL) has advantages of compactness, high-efficiency, and long lifetime [1-3]. DPSSLs are capable to generate pulsed lasers at high-repetition rate, but the average power is restricted to a low level due to thermal effects. Pulse burst technique is a promising approach to provide a series of high energy pulses at high repetition rate in a short time duration [4-6]. It is especially useful for applications in laser diagnostic of turbulent flow fields characterized by turbulent time in the order of microseconds. In recent years, pulse burst laser with laser diode (LD) side-pumped amplifiers have been developed
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IP T
and utilized in laser-based diagnostics [7-9]. Composite laser rod with un-doped cap and saturable absorber is effective approach to get compact pulsed laser at high repetition rate [10, 11]. In previous study, a directly-pumped YAG/Nd:YAG/Cr4+:YAG pulse burst laser is reported with a single pulse energy of 210 μJ and a repetition rate of 11 kHz [12]. But the repetition and efficiency is limited due to the low absorption efficiency. In this paper, we present a high-repetition-rate, high-peak-power burst mode 1064 nm laser with a YAG/Nd:YAG/Cr4+:YAG composite crystal pumped by an 808 nm LD. The output laser performances with different pump beam radii are compared. With a pump radius of ωp=240 μm, the pulse burst energy of 13.2 mJ is obtained at 31.1 kHz, corresponding to an optical-to-optical efficiency of 27.2% and a single pulse energy of 425.8 μJ. The pulse width keeps nearly invariable during the pump region and the shortest pulse width is 1.9 ns. The beam quality factors are calculated to be Mx2=1.5 and My2 =1.7 by using the travelling knife-edge method. The maximum single pulse energy of 710 μJ is obtained at 10.2 kHz with a peak power of 373.7 kW.
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2. Experimental setup
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The experimental setup of 808 nm LD pumped burst mode laser with a YAG/Nd:YAG/Cr4+:YAG composite crystal is shown in Fig.1. The pump source is a fiber coupled LD at 808 nm with a maximum power of 50 W. The fiber diameter is 400 μm and the numerical aperture (N.A.) is 0.22. The pump duration is set at 1ms, long enough for high-speed turbulent flow diagnostic and the repetition rate is 100 Hz. The pump beam is re-imaged into laser rod by coupling systems with different coupling ratios. A composite YAG/Nd:YAG/Cr4+:YAG crystal serves as laser medium and Qswitch with a dimension of (2+5.5+1.5)×3×3 mm3. Both end faces are coated with high transmission at 1064 nm and 808 nm. The doping concentration of Nd:YAG is 1.0at.% and the initial transmission of Cr4+:YAG saturable absorber is T0=40% at 1064 nm. The rod is wrapped with indium folder, mounted in heat sink and kept at 20 ℃ by water cooling. The laser resonator is composed with two plane mirrors and the transmission of output coupler is T=40% at 1064 nm. The geometric length of laser cavity is 25 mm. The pulse characters of pulse burst laser are measured by a photodiode (DET10A, Thorlabs Inc.) and recorded by a digital oscilloscope (DSO-X 3034A, Agilent Technologies Inc.).
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3. Experimental results and discussions The output wavelength of LD is measured to be around 807 nm with a full width at half maximum (FWHM) of 1.5 nm. The absorption efficiency of Nd:YAG is estimated to be 70%. Output pulse energy of 808 nm LD pumped YAG/Nd:YAG/Cr4+:YAG pulse burst laser with different pump beam radii is investigated, as shown in Fig. 2. The pulse burst energy increase linearly with incident pump energy and the maximum efficiency is achieved with a pump beam radius of ωp=240 μm. At the incident pump energy of 48.5 mJ, the maximum energy reaches 13.2 mJ with an optical-to-optical efficiency of 27.2%. The threshold pump power with a pump beam radius of ωp=166μm is lowest
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due to high pump density, but the laser efficiency is reduced at higher pump energy because of lower overlap efficiency. The maximum output burst energies are 11.2 mJ and 7.1 mJ respectively when the pump beam radii are ωp=380 μm and ωp=166 μm. Figure 3 presents pulse repetition rate of pulse burst laser versus incident pump energy. The pulse repetition rate and pulse number in a burst increase with pump power. With a pump beam radius of ωp=166 μm, a repetition rate of 67.4 kHz is obtained, which is higher than 31.1 kHz and 10.2 kHz with pump beam radii of ωp=240μm and ωp=380μm. There are 67 pulses in the pulse burst duration of 1 ms with a single pulse energy of 171 μJ. The highest single pulse energy of 710 μJ is achieved at 10.2 kHz with a pump beam radius of ωp=380 μm. The temporal pulse train of 31.1 kHz is given in Fig. 4 and no pulse lost is observed. The variation of pulse width as the function of incident pump energy is given in Fig. 5. It could be seen that the pulse width keeps nearly constant around 2 ns within the whole pump region. It could be ascribed to the changeless value of the modulation depth during passively Q-switching operation [13]. The shortest pulse width of 1.9 ns is obtained with a pump beam radius of ωp=240 μm. The temporal pulse profile of 1.9 ns is illustrated in Fig. 6, which has a sharp rising edge. The maximum peak power is calculated to be 373.7 kW at 10.2 kHz in the pulse burst laser. The peak powers reach 72.8 kW at 67.4 kHz and 212.9 kW at 31.1 kHz. The beam density distribution of pulse burst laser at 31.1 kHz is measured by a laser beam analyzer (LBA-712PC-D, Spiricon Inc.), as shown in Fig. 7. It shows good symmetry in both directions. By using the travelling knife-edge method [14], the beam radius variation of pulse burst laser at 31.1 kHz is measured, as given in Fig. 8. The beam quality factors are calculated to be Mx2=1.5 and My2 =1.7 by fitting these data to Gaussian beam propagation expression.
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4. Conclusions
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In conclusion, we presented a high-repetition-rate, high-peak-power LD pumped burst mode 1064 nm laser with a YAG/Nd:YAG/Cr4+:YAG composite crystal. The output laser performances with different pump beam radii are investigated. When the pump radius is ωp=240 μm, the pulse burst energy at 1064 nm reaches 13.2 mJ with an opticalto-optical efficiency of 27.2% and a single pulse energy of 425.8 μJ. The maximum repetition rate of 67.4 kHz is achieved with a pump beam radius of ωp=166 μm. The pulse width keeps nearly invariable during the pump region and the shortest pulse width reaches 1.9 ns. The maximum single pulse energy of 710 μJ is obtained at 10.2 kHz with a peak power of 373.7 kW by using a pump beam radius of ωp=380 μm. By using the travelling knife-edge method, the beam quality factors at 31.1 kHz are measured to be Mx2=1.5 and My2 =1.7. The pulse energy would be further amplified to satisfied the requirement in laser based diagnostics. Acknowledgements This work was supported by the National Natural Science Foundation of China (NSFC) (61605032 and 61505042), Shenzhen Science and Technology Program (JSGG20170414141239041), General Financial Grant from the China Postdoctoral
Science Foundation (Grant No. 2015M80263), the Fundamental Research Funds for Central Universities (Grant No. HIT. NSRIF. 2017018).
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References 1. G. Huber, C. Kränkel, K. Petermann, Solid-state lasers: status and future, J. Opt. Soc. Am. B, 27(11) (2010), B93-B105. 2. T. Y. Fan and R. L. Byer, Modeling and cw operation of a quasi-three-level 946 nm Nd:YAG laser, IEEE J. Quantum. Electron. 23 (1987), 605-612. 3. X. Fu, Q. Liu, X. Yan, J. Cui, and M. Gong, 120 W high repetition rate Nd:YVO4 MOPA laser with a Nd:YAG cavity-dumped seed laser, Appl. Phys. B. 95 (2009), 63-67. 4. B. Thurow, N. Jiang, W. Lempert, Review of ultra-high repetition rate laser diagnostics for fluid dynamic measurements, Meas. Sic. Technol., 24 (2013) 012002. 5. B. Thurow, A. Satija, K. Lynch, Third-generation megahertz-rate pulse burst laser system, Appl. Opt. 48(11) (2009), 2086-2093. 6. M. Slipchenko, J. Miller, S. Roy, J. Gord, T. Meyer, All-diode-pumped quasicontinuous burst-mode laser for extended high-speed planar imaging, Opt. Express, 21(1) (2013), 681-689. 7. P. Wu, W. Lempert, and R. Miles, Megahertz pulse-burst laser and visualization of shock-wave/ boundary-layer interaction, J. AIAA, 38(4) (2000), 672-679. 8. J. Miller, S. Engel, J. Troger, Characterization of a CH planar laser-induced fluorescence imaging system using a kHz-rate multimode-pumped optical parametric oscillator, Appl. Opt. 51(14) (2012), 2589-2600. 9. R. Pan, U. Retzer, T. Werblinski, M. Slipchenko, T. Meyer, L. Zigan, S. Will, Generation of high-energy, kilohertz-rate narrowband tunable ultraviolet pulses using a burst-mode dye laser system, Opt. Lett. 43(5) (2018) 1191-1194. 10. W. Jiang, Y. Liu, W. Chen, S. Zhu, Z. Chen, G. Zhang, Y. Chen, Z. Chen, Composite Yb:YAG/Cr4+:YAG/YAG crystal passively Q-switched lasers at 1030 nm, Appl. Opt. 54(7) (2015) 1834-1838. 11. Q. Zhou, S. Zhu, W. Jiang, Z. Li, Y. Wang, H. Yin, Z. Chen, J. Yuan, Diode-endpumped passively Q-switched blue laser with Nd:YAG/YAG/Cr4+:YAG/YAG composite crystal, Optik, 127 (2016) 10588-10592. 12. X. Li, Y. Zhou, R. Yan, D. Wang, X. Fa, Y. Ma, Z. Zhou, A compact pulse burst laser with YAG/Nd:YAG/Cr4+:YAG composite crystal, Optik, 136 (2017) 107-111. 13. R. Yan, X. Yu, Y. Ma, X. Li, D. Chen and J. Yu, High-peak-power, short-pulsewidth, LD end-pumped, passively Q-switched Nd:YAG 946 nm laser, Opt. Commun., 285 (2012), 4462-4465.
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14. J. M. Khosrofian and B. A. Garetz, Measurement of a Gaussian laser beam diameter through the direct inversion of knife-edge data, Appl. Opt. 22(21) (1983), 34063410.
Figure captions
Laser Diode
Coupling Optics
Fiber
M1
M2 YAG+Nd:YAG+Cr:YAG Laser output
IP T
Figure 1. Experimental setup 15
wp=240mm
SC R
wp=380mm
10
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Pulse busrt energy (mJ)
wp=166mm
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Fig. 2. Output pulse burst energy versus incident pump burst energy with different pump radii
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wp=166mm wp=240mm wp=380mm
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Pulse repetition rate (kHz)
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Fig. 3. Pulse repetition rate versus incident pump energy with different pump radii
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Fig. 4. Temporal pulse train of pulse burst laser at 31.1 kHz
Incident pump energy (mJ)
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Fig. 5. Variation of pulse width versus incident pump energy with different pump radii 10
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Fig. 6. Temporal pulse profile of 1.9 ns
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50
60
70
80
90
100
Location (mm)
CC E
PT
ED
Fig. 8. Beam radius variation of pulse burst laser at 31.1 kHz
A
IP T
Fig. 7. The laser density distribution of pulse burst laser