Efficient nonlinear conversion of frequency stable lasers.

摘要

Diode-laser-pumped monolithic Nd:YAG nonplanar ring oscillators produce frequency-stable single-mode output at 1.064 {dollar}mu{dollar}m. Efficient nonlinear conversion of this output is demonstrated using field enhancement techniques. The use of low loss MgO:LiNbO{dollar}sb3{dollar} and novel monolithic cavity designs, where the mirrors are deposited directly on the crystal, has allowed 56% efficient cw second harmonic generation and greater than 60% efficient parametric oscillation.; A theory of second harmonic generation using an external cavity resonant at the fundamental is presented that extends previous work to include conversion of the resonated wave to the harmonic field. An impedance-matched 12.5 mm long monolithic MgO:LiNbO{dollar}sb3{dollar} ring cavity doubler is used to produce 29.7 mW of cw, single-axial-mode 532-nm radiation from an input of 52.6 mW for a conversion efficiency of 56%.; A monolithic MgO:LiNbO{dollar}sb3{dollar} doubly resonant optical parametric oscillator (DRO) was operated near degeneracy, pumped by the output of the resonant doubler with the laser producing relaxation oscillation pulses. Pump depletions for the DRO of greater than 60% were observed when pumped with peak powers six times above the calculated 40-mW cw threshold. The DRO output was temperature tuned from 1.01 {dollar}mu{dollar}m to 1.13 {dollar}mu{dollar}m, producing single axial mode output over much of the range.; A monolithic MgO:LiNbO{dollar}sb3{dollar} singly resonant optical parametric oscillator (SRO) was pumped as both a standing wave and a ring geometry resonator by a long-pulse amplified and frequency-doubled laser. Pump depletions of greater than 60% were observed when pumping four times above the calculated 35-Watt threshold. The SRO output at the resonant signal tuned with temperature from 834 nm to 958 nm while the corresponding idler tuned from 1.47 {dollar}mu{dollar}m to 1.2 {dollar}mu{dollar}m.