Diode Pumped High Peak Power Quasi Q-Switched and Passively Q-Switched Nd:YVO₄ Lasers at 1064 nm and 532 nm using Cr:YAG and KTP crystals

Ashraf F. El-Sherif, Mahmoud M. Talat

Military Technical Institute, Cairo, Egypt.
Townes Laser Institute, CREOL College of Optics and Photonics, University of Central Florida, Orlando, USA.

DOI: 10.4236/opj.2013.31009                

Abstract

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.

Keywords

High Power Diode Laser; High Power Nd:YVO₄ Laser; Cr:YAG Saturable Absorber Mirror; Passive Q-Switching; KTP Crystal; Self Q-Switching; Special Cooling System

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	J. M. Yang, J. Liu and J. L. He, “Efficient Diode-Pumped Nd:YVO4 Continuous-Wave Laser at 1. 34 ?m,” Optics, Vol. 115, No. 12, 2004, pp. 538-540. doi:10.1078/0030-4026-00538
[2]	H. R. Zhang, M. J. Chao, M. Y. Gao, L. W. Zhang and J. Q. Yao, “High Power Diode Single-End-Pumped Nd: YVO4 Laser,” Optics & Laser Technology, Vol. 35, No. 6, 2003, pp. 445-449. doi:10.1016/S0030-3992(03)00051-3
[3]	G. P. Agrwal, “Semiconductor lasers,” 2nd Edition, Van Nostrand Reinhold, New York, 1993.
[4]	W. Streifer, D. R. Scifres, G. L. Hrnagel, D. F. Welch, J. Berger and M. Sakamoto, “Advances in Diode Laser Pumps,” IEEE Journal of Quantum Electronics, Vol. 24, No. 6, 1988, pp. 883-894.
[5]	D. F. Welch, “A Brief History of High-Power Semiconductor Lasers,” IEEE Journal of Quantum Electronics, Vol. 6, No. 6, 2000, pp. 1470-1477.
[6]	D. Jaque, J. J. Romero, Y. Huang and Z. D. Luo, “Tunable Green Laser Source Based on Frequency Mixing of Pump and Laser Radiation from a Nd:YVO4 Crystal Operating at 1342 nm with an Intracavity KTP Crystal,” Applied Optics, Vol. 41, No. 30, 2002, pp. 6394-6398. doi:10.1364/AO.41.006394
[7]	J. E. Bernard, V. D. Lokhnygin and A. J. Alcock, “Grating-Tuned, Single-Longitudinal-Mode, Diode Pumped Nd:YVO4 Laser,” Optics Letters, Vol. 18, No. 23, 1993, pp. 2020-2023. doi:10.1364/OL.18.002020
[8]	Y. F. Chen, “Ef?cient Subnanosecond Diode-Pumped Passively Q-Switched Nd:YVO4 Self-Stimulated Raman Laser,” Optics Letters, Vol. 29, No. 11, 2004, pp. 1251-1253. doi:10.1364/OL.29.001251
[9]	R. Scheps, J. F. Myers and G. Mizell, “High-Effciency 1.06 Micrometer Output in a Monolithic Nd:YVO4 Laser,” Applied Optics, Vol. 33, No. 24, 1994, pp. 5546- 5550. doi:10.1364/AO.33.005546
[10]	Y. F. Chen, K. F. Huang, S. W. Tsai, Y. P. Lan, S. C. Wang and J. Chen, “Simultaneous Mode Locking in a Diode-Pumped Passively Q-Switched Nd:YVO4 Laser with a GaAs Saturable Absorber,” Applied Optics, Vol. 40, No. 33, 2001, pp. 6038-6041. doi:10.1364/AO.40.006038
[11]	J. Liu, B. Ozygus, S. Yang, J. Erhard, U. Seelig, A. Ding, H. Weber, X. Meng, L. Zhu, L. Qin, C. Du, X. Xu and Z. Shao, “Ef?cient Passive Q-Switching Operation of a Di ode-Pumped Nd:GdVO4 Laser with a Cr4+:YAG Saturable Absorber,” Journal of the Optical Society of America B, Vol. 20, No. 4, 2003, pp. 652-661. doi:10.1364/JOSAB.20.000652
[12]	J. A. Morris and C. R. Pollock, “Passive Q-Switching of a Diode Pumped Nd:YAG Laser with a Saturable Absorber,” Optics Letters, Vol. 15, No. 8, 1990, pp. 440-442. doi:10.1364/OL.15.000440
[13]	R. S. Conroy, T. Lake, G. J. Friel, A. J. Kemp and B. D. Sinclair, “Self Q-Switched Nd:YVO4 Microchip Laser,” Optics Letters, Vol. 23, No. 6, 1998, pp. 457-459. doi:10.1364/OL.23.000457
[14]	Y. X. Leng, L. H. Lin, Y. B. Ou and X. K. Wan, “Ab sorption of Excited State of Cr:YAG Crystal,” Acta Optica Sinica, Vol. 21, No. 2, 2001, pp. 225-227.
[15]	Y. Shimony, Z. Burshtein and B. A. Ben-Amar, “Repetitive Q-Switching of a CW Nd:YAG Laser Using Cr:YAG Saturable Absorber,” IEEE Journal of Quantum Elec tronics, Vol. 32, No. 2, 1996, pp. 305-310. doi:10.1109/3.481878
[16]	X. Zhang, S. Zhao and Q. Wang, “Laser Diode Pumped Cr:YAG Passively Q-Switched Nd:S-FAP Laser,” Optics Communications, Vol. 155, No. 1-3, 1998, pp. 55-60. doi:10.1016/S0030-4018(98)00356-3
[17]	Z. Ma, D. J. Li, J. C. Gao, N. L. Wu and K. M. Du, “Thermal Effects of the Diode End-Pumped Nd:YVO4 Slab,” Optics Communications, Vol. 275, No. 1, 2007, pp. 179-185. doi:10.1016/j.optcom.2007.03.024
[18]	J. L. Blows, T. Omatu, J. Dawes, H. Pask and M. Tateda, “Heat Generation in Nd:YVO4 with and without Laser Action,” IEEE Photonics Technology Letters, Vol. 10, No. 12, 1998, pp. 1727-1729. doi:10.1109/68.730483
[19]	T. Y. Fan, “Heat Generation in Nd:YAG and Yb:YAG,” IEEE Journal of Quantum Electronics, Vol. 29, No. 6, 1993, pp. 1457-1459. doi:10.1109/3.234394
[20]	Z. Xiong, Z. G. G. Li, N. Moore, W. L. Huang and G. C. Lim, “Detailed Investigation of Thermal Effects in Lon gitudinally Diode-Pumped Nd:YVO4 Lasers,” IEEE Journal of Quantum Electronics, Vol. 39, No. 8, 2003, pp. 979-986. doi:10.1109/JQE.2003.814371
[21]	W. Koechner, “Solid State Laser Engineering,” 3rd Edition, Spronge-Verlag, Berlin, 1992, pp. 381-413.
[22]	A. M. Samy, A. F. El-Sherif, A. M. Mokhtar and M. F. Hassan, “Simulation and Analysis of a High Power Diode-End-Pumped Nd:YVO4 Solid-State Laser,” Proceedings of 4th International Conference on Engineering Mathematics and Physics, Cairo, May 2008, pp. 231-241.
[23]	A. F. El-Sherif, M. F. Hassan, A. M. Mokhtar and A. M. Samy, “Characterization of a 808 nm High Power Diode Laser Module,” Proceedings of 4th International Conference on Engineering Mathematics and Physics, Cairo, May 2008, pp. 242-251.
[24]	D. Jaque, J. J. Romero, Y. Huang and Z. D. Luo, “Tunable Green Laser Source Based on Frequency Mixing of Pump and Laser Radiation from a Nd:YVO4 Crystal Operating at 1342 nm with an Intracavity KTP Crystal,” Applied Optics, Vol. 41, No. 30, 2002, pp. 6394-6398. doi:10.1364/AO.41.006394
[25]	J. E. Bernard, V. D. Lokhnygin and A. J. Alcock, “Grating-Tuned, Single-Longitudinal-Mode, Diode-Pumped Nd:YVO4 Laser,” Optics Letters, Vol. 18, No. 23, 1993, pp. 2020-2023. doi:10.1364/OL.18.002020
[26]	Y. F. Chen, “Ef?cient Subnanosecond Diode-Pumped Passively Q-Switched Nd:YVO4 Self-Stimulated Raman Laser,” Optics Letters, Vol. 29, No. 11, 2004, pp. 1251 1253. doi:10.1364/OL.29.001251
[27]	R. Scheps, J. F. Myers and G. Mizell, “High-Efficiency 1.06-Micrometer Output in a Monolithic Nd:YVO4 Laser,” Applied Optics, Vol. 33, No. 24, 1994, pp. 5546 5550. doi:10.1364/AO.33.005546
[28]	Y. F. Chen, K. F. Huang, S. W. Tsai, Y. P. Lan, S. C. Wang and J. Chen, “Simultaneous Mode Locking in a Diode-Pumped Passively Q-Switched Nd:YVO4 Laser with a GaAs Saturable Absorber,” Applied Optics, Vol. 40, No. 33, 2001, pp. 6038-604. doi:10.1364/AO.40.006038
[29]	J. Liu, B. Ozygus, S. Yang, J. Erhard, U. Seelig, A. Ding, H. Weber, X. Meng, L. Zhu, L. Qin, C. Du, X. Xu and Z. Shao, “Efficient Passive Q-Switching Operation of a Diode-Pumped Nd:GdVO4 Laser with a Cr4+:YAG Saturable Absorber,” Journal of the Optical Society of America B, Vol. 20, No. 4, 2003, pp. 652-661. doi:10.1364/JOSAB.20.000652
[30]	J. A. Morris and C. R. Pollock, “Passive Q-Switching of a Diode-Pumped Nd:YAG Laser with a Saturable Ab sorber,” Optics Letters, Vol. 15, No. 8, 1990, pp. 440-442. doi:10.1364/OL.15.000440
[31]	R. S. Conroy, T. Lake, G. J. Friel, A. J. Kemp and B. D. Sinclair, “Self Q-Switched Nd:YVO4 Microchip Laser,” Optics Letters, Vol. 23, No. 6, 1998, pp. 457-459. doi:10.1364/OL.23.000457
[32]	Z. Zalevsky, Y. Kapellner, I. Eyal and N. Cohen, “Self Q-Switching Effect in a Nd:YVO4/KTP Lasing Unit,” Optical Engineering, Vol. 45, No. 7, 2006, Article ID: 070506.