EYE-SAFE KGd(WO₄)₂RAMAN LASERS:A COMPARATIVE STUDY AT PUMPINGBY Nd:KGd(WO₄)₂ LASERS WITH⁴F_3/2®⁴I_11/2 AND⁴F_3/2®⁴I_13/2 WORKING TRANSITIONS

A comparative study of eye-safe extracavity KGW Raman lasers that convert multimode radiation from Nd:KGW lasers operating on⁴F_3/2-⁴I_11/2 and⁴F_3/2-⁴I_13/ transitions into the third Stokes component at l = 1500 nm and the first Stokes component at l = 1507 or 1538 nm, respectively, was carried out. For the same sizes of laser and Raman elements, Raman laser emitting the third Stokes component provides higher power and energy of the pulse (~14.2 mJ) and smaller divergence of the Stokes beam (~9.4 mrad) at lower pump energy of Nd:KGW laser (~6.7 J). At the pump pulse energy of 29-34 mJ, all Raman lasers have the same optical efficiency reaching 36 %. However, in terms of the electrical energy delivered to the flashlamp, the total efficiency of the Raman laser of the third Stokes component is »1.7 times larger. The duration of Raman pulses is comparable to that of pump pulses and is ~20 ns for the first Stokes components. The pulse of the third Stokes component is shorter by a factor of 2.5-3. Because of different pump levels and different strength of thermo-optical distortions of Nd:KGW laser elements, the energy density distribution for the beams of the first Stokes component is elliptical, while it is almost circular for the beam the of the third Stokes component. The possibility of simultaneous lasing at wavelengths of 1507 and 1538 nm in parallel and orthogonal polarizations of Stokes waves is shown.

вынужденное комбинационное рассеяние, внeрезонаторный KGW ВКР-лазер, многомодовый KGW:Nd-лазер накачки, первая и третья стоксовы компоненты, безопасное для глаз излучение, stimulated Raman scattering, extracavity KGW Raman laser, multimode Nd:KGW pump laser, first and third Stokes components, eye-safe radiation

1. D. C. Hanna, D. J. Pointer. Opt. Commun., 60, N 3 (1986) 187-190

2. Z. Chu, U. N. Singh, T. D. Wilkerson. Opt. Commun., 75, N 2 (1990) 173-178

3. P. G. Zverev, T. T. Basiev, A. M. Prokhorov. Opt. Mater., 11 (1999) 335-352

4. N. Tkei, S. Suzuki, F. Kannari. Appl. Phys. B, 74 (2002) 521-527

5. V. A. Lisinetskii, H. J. Eichler, H. Rhee, X. Wang, V. A. Orlovich. Opt. Commun., 281 (2008) 2227-2232

6. R. Chulkov, V. Lisinetskii, O. Lux, H. Rhee, S. Schrader, H. J. Eichler, V. Orlovich. Appl. Phys. B, 106 (2012) 867-875

7. P. V. Shpak, S. V. Voitikov, R. V. Chulkov, P. A. Apanasevich, V. A. Orlovich, A. S. Grabtchikov, A. Kushwaha, N. Satti, L. Agrawal, A. K. Maini. Opt. Commun., 285 (2012) 3659-3664.

8. В. И. Дашкевич, В. А. Орлович, А. П. Шкадаревич. Журн. прикл. спектр., 76, № 5 (2009) 725-732 [V. I. Dashkevich, V. A. Orlovich, A. P. Shkadarevich. J. Appl. Spectr., 76, N 5 (2009) 685-691]

9. J. T. Murray, W. L. Austin, R. C. Powell. Opt. Mater., 11 (1999) 353-371

10. J. T. Murray, R. C. Powell, N. Peyghambarian, D. Smith, W. Austin, R. A. Stolzenberger. Opt. Lett., 20 (1995) 1017-1019

11. D. Sakaizawa, Ch. Nagasawa, T. Nagai, M. Abo, Y. Shibata, M. Nakazato. J. Appl. Phys., 47, N 3 (2008) 1612-1614

12. N. S. Ustimenko, E. M. Zabotin. Proc. SPIE, 5447 (2005) 30-38

13. N. S. Ustimenko, A. V. Gulin, V. A. Pashkov. Proc. SPIE, 4723 (2002) 69-72

14. Huang Jianhong, Lin Jipeng, Su Rongbing, Li Jinghui, Zheng Hui, Xu Canhua, Shi Fei, Lin Zongzhi, Zhuang Jian, Zeng Wenrong, Lin Wenxiong. Opt. Lett., 32 (2007) 1096-1098

15. Y. F. Chen. Opt. Lett., 29 (2004) 2172-2174

16. Y. F. Chen. Opt. Lett., 29 (2004) 2632-2634

17. В. И. Дашкевич, А. И. Водчиц, В. А. Орлович, Н. С. Казак, В. К. Павленко, В. И. Покрышкин, И. П. Петрович, В. В. Руховец. Журн. прикл. спектр., 73, № 4 (2006) 535-543 [V. I. Dashkevich, A. I. Vodchits, V. A. Orlovich, N. S. Kazak, V. K. Pavlenko, V. I. Pokryshkin, I. P. Petrovich, V. V. Rukhovets. J. Appl. Spectr., 73, N 4 (2006) 604-612]

18. I. V. Mochalov. Opt. Eng., 36 (1997) 1660-1669

19. V. L. Kalashnikov. Opt. Commun., 218 (2003) 147-153

20. N. Hodgson, H. Weber. Laser Resonatord and Beam Propagation: Fundamentals, Advanced Concepts and Applications, 2nd ed., Springer (2005)