Broadly Tunable Intracavity Zinc Germanium Phosphate Optical Parametric Oscillator for Hyperspectral Imaging

We report, to our knowledge, the first operation of a singly-resonant intracavity optical parametric oscillator (OPO) using the nonlinear material zinc germanium phosphate. The broadly tunable OPO uses a 7-W cw thulium fiber laser pump source to produce > 100 mW of tunable mid-infrared light at repetition rates up to 30 kHz. The measured tuning range is 5.5 to 10 mu m. The compact, low threshold source was used to perform spectroscopy of various substances. In addition, hyperspectral images were taken by combining the system with a scanning mirror pair and infrared photodiode. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)