Characterization of an Inracavity optical parametric oscillator

The wavelength of laser radiation can be converted by using nonlinear optical crystals. One nonlinear process is parametric oscillation where a fundamental wavelength is converted into two longer wavelengths. In this work the possibilities to build a stable source producing radiation in the 2 µm wavelength region was investigated. This radiation can, in further conversion processes, generate longer wavelengths with applications in e.g. laser countermeasures and laser for atmospheric remote sensing. An intracavity Optical Parametric Oscillator (OPO) using the nonlinear crystal KTiOPO4 (KTP) was designed to convert pulsed Nd:YAG laser radiation operating at 1064 nm wavelength to regions around 2 µm. The maximum converted output power achieved for an intracavity OPO configuration was 2.5 W using a Nd:YAG output power of 20 W. An analysis of thermal lensing of the laser rod and the influence from thermal effects on output power from the system was carried out.