Conditions for gain and threshold of the inversionless laser are derived as a function of pump strength and relaxation rates. It is shown that lasing without inversion can be achieved most easily only in systems in which either conventional or Raman lasing is attainable. The threshold of the inversionless laser is shown to be orders of magnitude higher than that of the conventional laser. Practical implications, especially for intersubband lasers, are discussed.
© 1997 Optical Society of America
Jacob B. Khurgin and Emmanuel Rosencher, "Practical aspects of optically coupled inversionless lasers," J. Opt. Soc. Am. B 14, 1249-1253 (1997)