Passive laser Q-switches based on MeF2:Nd2+ (Me-Ca Sr Ba) crystals

摘要

Abstract: ent the results of investigations of nonlinear absorption in alkaline-earth fluoride crystals containing divalent neodymium ions, and also the results of utilizing these crystals for passive Q-switching and mode-locking in solid state lasers radiating in the wavelength range (1.3 - 1.6) $mu@m. Spectroscopic parameters of the studied materials such as the effective absorption cross-section and the relaxation time of the state of self-induced transparency (SIT) were estimated. The nature of the residual absorption was determined in these crystals and a simple spectroscopic model describing the SIT process in MeF$-2$/:Nd$+2$PLU$/-crystals is offered. It is demonstrated that MeF$-2$/:Nd$+2$PLU$/-crystals can be used as Q- switches for the lasers of the near IR wavelength range. The results of Q-switching of neodymium and erbium lasers generating in the ranges of 1.3 and 1.54 $mu@m, respectively, are presented. The single-peak generation regime and generation of a train of modulated pulses are investigated. The use of SrF$- 2$/:Nd$+2$PLU$/-crystals allowed us to realize the mode-locked regime in YAG:Nd-crystal laser, operating on the transition $+4$/F$-3/2$/ $YLD $+4$/I$-13/2$/. Evaluation of the duration of peaks gives the time less than 400 psec. !22