Thermal optical properties, Q-switching and frequency tuning of an Nd: LGGG laser based on the 4F3/2 → 4I13/2 transition of a neodymium ion

Laser characteristics of continuous-wave (cw) and passively Q-switched Nd: LGGG lasers based on the F-4(3/2) -> I-4(13/2) transition of an neodymium ion are investigated. The lasing spectra of the cw and the Q-switching regimes are studied in detail. The thermal optical coefficient for the Nd:LGGG crystal at a wavelength of 1.33 mu m is estimated to be 15.3 x 10(-6) K-1. By inserting a quartz plate at the Brewster angle, the frequency of the Nd: LGGG laser is tuned. In the cw regime, the maximum output power at an incident pump power of 7.09 W is 802 mW and a slope efficiency is 13.2%. In the Q-switching regime, a minimum pulse duration of 9.75 ns is obtained with an output power of 176 mW and a repetition rate of 8 kHz. The maximum pulse energy and the highest peak power are 25.4 mu J and 2.4 kW, respectively.