[1] G. F. Albrecht, S. B. Sutton, E. V. George, W. R. Sooy, and W. F. Krupke, Laser and Particle Beams 16, 605 (1998).

[2] R. Mark, D. Dane, and D. C. Brent, Photon. Spectra 38, (8) 44 (2004).

[3] G. F. Albrecht, S. B. Sutton, E. V. George, W. R. Sooy, and W. F. Krupke, Proc. SPIE 3343, 661 (1998).

[4] F. Jin and D. Zhou, Laser Technol. (in Chinese) 28, 534 (2004).

[5] W. Xie, J. Yu, and C. Bi, Chin. J. Lasers (in Chinese) 33, 70 (2006).

[6] H. Hu, J. Jiang, B. Tu, L. Cui, T. Zhou, Z. Cai, and C. Tang, Chin. J. Lasers (in Chinese) 32, 1485 (2005).

[7] X. Yuan, X. Jian, and D. Cao, Chin. J. Lasers (in Chinese) 33, 93 (2006).

[8] J. M. Eggleston, T. J. Kane, K. Kuhn, J. Unternahrer, and R. L. Byer, IEEE J. Quantum Electron. 20, 289 (1984).

[9] T. J. Kane, J. M. Eggleston, and R. L. Byer, IEEE J. Quantum Electron. 20, 289 (1984).

[10] J. Liu, J. Lu, and J. Lu, Chin. Phys. Lett. 16, 181 (1999).