Continuous Wave Intracavity Optical Parametric Oscillator using Second Harmonic Generation Noise Suppression.

A compact continuous wave (cw) optical parametric oscillator (OPO)capable of tuning over key absorption features in the infrared is a desirable tool for spectroscopy of key atmospheric pollutants, narcotics and explosives. A system that can combine broad tuneability with narrow linewidth allows probing of diverse substances with precision. M Squared Lasers already manufacture a pulsed (broad linewidth) OPO which is a compact, broadly tunable source and combines this with their imager to produce hyperspectral images. The challenge is to produce narrow linewidth by making a cw OPO. The inherent difficult is relaxation oscillations, which occur in the interplay between the OPO and the laser when they share a common resonator. We propose an internal SHG unit to suppress this.