[1] [1] J. J. Zayhowskii, J. Alloys Compound 303-304, 293 (2000).

[2] [2] E. Molva, Opt. Mater. 11, 289 (1999).

[3] [3] Y.-F. Chen and Y. P. Lan, Appl. Phys. B 74, 415 (2002).

[4] [4] O. B. Jensen, T. S. Kettrup, O. B. Petersen, and M. B. Larsen, J. Opt. A: Pure Appl. Opt. 4, 190 (2002).

[5] [5] A. S. Grabtchikov, R. V. Chulkov, V. A. Orlovich, M. Schmitt, R. Maksimenko, and W. Kiefer, Opt. Lett. 28, 926 (2003).

[6] [6] A. S. Grabtchikov, A. N. Kuzmin, V. A. Lisinetskii, G. I. Ryabtsev, V. A. Orlovich, and A. A. Demidovich, Appl. Phys. Lett. 75, 3742 (1999).

[7] [7] A. A. Demidovich, P. A. Apanasevich, L. E. Batay, A. S. Grabtchikov, A. N. Kuzmin, V. A. Lisinetskii, V. A. Orlovich, and O. V. Kuzmin, Appl. Phys. B 76, 509 (2003).

[8] [8] A. S. Grabtchikov, V. A. Lisinetskii, V. A. Orlovich, M. Schmitt, R. Maksimenko, and W. Kiefer, Opt. Lett. 29, 2524 (2004).

[9] [9] V. A. Orlovich, A. S. Grabtchikov, V. A. Lisinetskii, V. N. Burakevich, A. A. Demidovich, M. Schmitt, and W. Kiefer, in Technical Digest of Advanced Solid-State Photonics 2005 WA6 (2005).

[10] [10] A. V. Kachinski, V. A. Orlovich, A. A. Bui, V. D. Kopachevsky, A. V. Kudryakov, and W. Kiefer, Opt. Commun. 218, 351 (2003).