ERBIUM 3-MU-M LASER AS AN UP-CONVERSION SYSTEM

The possibilities to obtain efficient 3-mu m lasing in erbium systems on the self-saturated transition (4)/(11/2)-->(4)/(13,2) are analyzed. In the frame of the mathematical model based on analytical expression s for population inversion, photon flux density, and quantum efficienc y, obtained in the stationary regime, and which explains the main char acteristics of 3-mu m generation, the influence of various interaction mechanisms such as cross-relaxations, transfer to impurities, excited -state absorption (ESA) and so on is analyzed. It is shown that, altho ugh ESA from the terminal laser level could improve the generation cha racteristics, the driving mechanism for 3-mu m erbium lasers is the co operative upconversion from the terminal laser level. (C) 1996 Society of Photo-Optical instrumentation Engineers.