[1] [1] D. T. Hodges; Infrared Phys., 1978, 18, No. 5～6, 375.

[2] [2] Τ. Α. Detemple; “Pulsed optically pumped far infrared lasers", in "Infrared and Millimeter Waves Vol. 1, Sources of Radiation", Edited by K. J. Button, Chapter 3(1979).

[3] [3] K. Lipton et al.;Opt. Commun., 1979, 21, No. 1, 42.

[4] [4] P. Mathien et al.; IEEE J. Quant. Electr., 1977, QE-13, No. 6, 465.

[5] [5] P. Woskoboinikow et al., J. Appl. Phys., 1979, 50, No. 2, 1125.

[6] [6] A. Semet et al.; International Journat of Infrared and Mollimeter Waves, 1983, 4, No. 2 231.

[7] [7] M. R. Green et al.; J. Phys. D: Appl. Phys., 1980,13, No. 6, 1029.

[8] [8] Τ. Y. Chang; JOSA, 1976, 18, No. 4, 362.

[10] [10] D. Ε. Evans et al.; Opt. Commun., 1976, 18, No. 4, 479.

[11] [11] E. Armandillo et al.; Infrared Phys., 1979, 19, 273.

[14] [14] Τ. Y. Chang; IEEE J. Quant. Electr., 1977, QE-13, No. 12, 937.

[15] [15] E. Armandillo et al.; J. Phys. D: Appl. Phys.; 1978, 11, No. 4, 421.