光栅和FP选频单纵模被动调Q扭转模振荡折叠腔激光器
摘要
A passively Q-switched side-pumped laser with folded resonator is specially constructed for singlelongitudinal-mode smooth pulse output. Nd:YAG is chosen as the laser active medium and Cr 4+ :YAG as the saturable absorber medium. Additionally, the method of frequency selection by grating with 1200 line/mm and Fabry-Perot (F-P) etalon is used in the twisted-mode cavity. The single-frequency smooth pulses are produced with 10-Hz repetition rate, 20-ns pulse width, and 1.064-m wavelength. The probability of single-frequency laser output measured is over 99% by using the methods of Fourier analysis and F-P etalon multiple-beam interferometry at the threshold voltage. The measured near-field and far-field angles of divergence are 1.442 and 1.315 mrad, respectively. The values of M 2 are 1.32 and 1.31 separately with the knife-edge method. Single pulse at 1.064 m with the energy of 8.8 mJ is achieved in TEM00 mode.