Monolithic dual-polarization self-mode-locked Nd:YAG 946-nm lasers: controlling beat frequency and observation of temporal chaos

Abstract

The self-mode-locked (SML) operation at 946 nm can be achieved with a monolithic Nd:YAG crystal when the pump power is above the threshold of the multiple-longitudinal-mode generation. The SML output is further found to include two orthogonal polarization components with a beat frequency coming from the birefringence effect in the laser crystal. The beat frequency can be widely adjusted in the range of 5-220 MHz by controlling the cooling temperature. The present experiment also confirms the theoretical prediction that the two-mode operation generally exhibits the chaotic dynamics when the frequency difference is sufficiently close to the relaxation frequency.

2 µm vector mode-locked pulses from Tm:Y2O3 ceramics laser

“…Thévenin et al reported a first dual-polarization ML laser with Nd:YAG crystal, synchronously generating two-frequency combs associated with the two polarization eigenstates [24]. Recently, Cheng et al obtained monolithic dual-polarization self-ML Nd:YAG crystal 946 nm lasers with chaotic dynamics and tunable beat frequencies [25,26]. Liang et al reported an orthogonally polarized ML laser with an Nd:YVO 4 crystal, with a wavelength of 1342 nm and pulse repetition rates up to 6.45 GHz [27].…”