Coherence and two-color squeezing in doubly resonant optical parametric oscillators

Optical parametric oscillators (OPO's) are enjoying a revival of interest. New materials and improved pump sources are enabling OPO's to live up to their decades-old promise of providing efficient, narrowband, widely tunable sources of light. In this thesis I describe advances in efficient, high coherence OPO's achieved through the use of improved pump lasers and monolithic OPO resonator designs.;A doubly resonant optical parametric oscillator (DRO) fabricated from MgO:LiNbO;An alternate laser pump source was developed for greater power at 532 nm and increased reliability. A lamp-pumped, 13-watt cw Nd:YAG ring laser at 1064 nm was injection locked using a 40-mW single-frequency diode-laser-pumped Nd:YAG laser as the master oscillator. Over 200 mW of light at 532 nm could be obtained by single-pass frequency doubling in a 2-cm crystal of MgO:LiNbO;The monolithic doubly resonant OPO exhibited very high coherence. The linewidth of the DRO signal was less than 13 kHz, the DRO was shown to generate a phase-locked subharmonic of the pump at degeneracy (acting as a coherent ;'Two-color squeezing,' or sub-shot-noise correlations of the signal and idler amplitudes were observed in DRO's with various output couplings. The best results were obtained with a DRO with nominal 1.2% output coupling where two-color squeezing 54% below the shot-noise level was observed, in good agreement with theory.