Exploring the effect of transverse patterns on the temporal characteristics in self-mode-locked Nd: YVO[formula omitted] lasers

Abstract

We investigate the influence of transverse mode distribution on the self-mode-locked (SML) states by employing off-axis pumping in an Nd:YVO4 laser with a linear concave-plano cavity. The higher-order transverse modes in the cavity are excited by adjusting the off-axis pumping displacement, and the dependence of the time characteristics of the SML laser on the transverse modes is analyzed. When the laser cavity length is 50 mm, and the off-axis displacement is adjusted offsets in the radial x and y directions to be (0,0) μ m, (45,58) μ m, and (80,0) μ m, the laser is operated in the longitudinal SML state with a repetition rate of 2.72 GHz, the amplitude modulation mode-locked pulse with a modulation frequency of 0.68 GHz and a repetition rate of 2.72 GHz, and the total-self-mode-locked with a repetition rate of 0.68 GHz, respectively. The corresponding transverse mode patterns are TEM00, TEM00+TEM01+TEM10 superposition, and TEM00+TEM10+TEM20 superposition. Finally, numerical simulations reconstruct the experimental mode-locked pulse and the corresponding transverse mode patterns based on the theory of coherent superposition of laser modes.