Longitudinally diode-pumped continuous-wave 3.5-W green laser

Theoretical treatment, simulation, and experiments of doubly resonant sum-frequency mixing in an external resonator

We describe the theoretical treatment of the doubly resonant sum-frequency mixing in an external resonator. The nonlinear conversion efficiency is increased by the resonantly enhanced circulating powers at both wavelengths. The model predicts the circulating powers in the resonator at two input wavelengths: the powers that are reflected off the input coupler and the output power at the sum frequency. Numerical simulation gives the design optimization of the system. The result of the simulation is compared with the result of a continuous-wave 355-nm generation experiment, where 0.66-W of output power was obtained.

Elimination of chaos in a multilongitudinal-mode, diode-pumped, 6-W continuous-wave, intracavity-doubled Nd:YAG laser

We present a new stability mechanism in an intracavity-doubled Nd:YAG laser oscillating in a multi-fundamental-longitudinal mode. Self-mode-locked oscillation, in which phases of the modes give the destructive interference between the sum and doubling components, leads to the low-noise operation of the diode-pumped, >6-W cw green laser, which we previously demonstrated [Opt. Lett. 21 1912 (1996)]. This phase-locked mode of operation would reduce the nonlinear output coupling and ultimately eliminate the chaotic amplitude fluctuation from the so-called green problem. The internally reflected green light at the end mirror has a significant effect on phase locking and elimination of noise through parametric processes.

Intracavity second-harmonic generation with a periodically domain-inverted LiTaO(3) device

Efficient intracavity second-harmonic generation (SHG) based on a bulk-type quasi-phase-matched (QPM) SHG device in a LiTaO(3) crystal is demonstrated. The periodically domain-inverted regions were fabricated by a high-voltage application technique. The internal loss from the refractive-index change in the domain-inverted regions was reduced to less than 0.1% by an annealing technique. Intracavity frequency doubling of a Nd:YVO(4) laser with the QPM SHG device pumped by a laser diode was effected to generate 13-mW green light for a pump power of 130 mW without suffering transverse mode distortion from a photorefractive effect.