[1] [1] Sorokina I T, Vodopyanov K L. Solid-State Mid-Infrared Laser Sources. New York: Springer, 2003. 1.

[2] [2] Aggarwal I D, Shaw L B, Sanghera J. Chalcogenide Glass for Mid- and Longwave IR Fiber Lasers. Washington: SPIE, 2005. 242.

[3] [3] Moizan V, Nazabal V, Troles J, et al. Optical Materials, 2008, 31: 39.

[4] [4] Aggarwal I D, Sanghera J S. J. Optoelectron. Adv. M, 2002, 4(3): 665.

[7] [7] Hommerich U, Brown E, Amedzake P, et al. J. Appl. Phys, 2006, 100: 113507.

[8] [8] Shin Y B, Cho W Y, Heo J. J. Non-Cryst. Solids, 1996, 208: 29.

[9] [9] Schweizer T, Samson B N, Hector J R, et al. J. Opt. Soc. Am. B, 1999, 16(2): 308.

[10] [10] Němec R, Frumarová B, Frumar M. J. Non-Cryst. Solids, 2000, 270: 137.

[11] [11] Judd B R. Phys. Rev., 1962, 127: 750.

[12] [12] Ofelt G S. Chem. Phys, 1962, 37: 511.

[13] [13] Němec P, Frumarová B, Frumar M, et al. Phys. Chem. Solids, 2000, 61: 1583.

[14] [14] Doualan J L, Girard S, Haquin H, et al. Optical Materials, 2003, 24: 563.

[15] [15] Naftaly M, Shen S X, Jha A. Applied Optics, 2000, 39(27): 4979.

[16] [16] Rademaker K, Krupke W F, Page R H, et al. J. Opt. Soc. Am. B, 2004, 21: 2117.

[17] [17] Wood D L, Tauc J. Phys.Rev. B, 1972, 5(8): 3144.

[18] [18] Reisfeld R, Jorgensen C K. Excited State Phenomena in Vitreous Materials, in Handbook on the Physics and Chemistry of Rare Earths, Vol. 9. Gschneider Jr K A and Eyring L, 1987. 58.

[19] [19] Miyakawa T, Dexter D L. Phys. Rev. B, 1970, 1(7): 2961.