High Speed Solid State Mid-Infrared Spectral Tuner for Laser Radar Applications

The Army has a need for a compact high-speed solid state hyperspectral tuner for rapildy tuning mid-infrared lasers and optical parametric oscillatorrs operating in the 3-5 micron range. Such electronic tunable source is needed in laser radar and Lidarsystems for various applications such as countermeasures and standoff detection of chemical and biological weapons. Present techniques are bulky and suffer from critical alignment, poor reliabiltiy from moving parts, and slow tuning rates. The objectiveis to construct and demonstrate a high-speed spectral tuner in the 3-5 micron range based on acousto-optic techniques. Based on experimental results, the oprojected performance of two types of AO tuners are: 1cm^-1 resolution and 95% efficiency at 1 wattdrive power. Using a transverse configuration, the tuning speed is estimated about 1MHz. The proposed approach is to use the above design as a low-risk baseline. Performance enhancement techniques are proposed to significantly improve the performance.The onbjective is to overcome the limitations including spectral resolution (2.2cm^-1), transmission efficicency (97%) and beam quality. All these factors will greatly affect the performance of the tunable OPOs.A rugged, field-deployable non-mechanicalacousto-optic tuner for OPOs will have many military applications. The near-term applications with the largest potential markets are chemical detection systems for environmental monitoring systems and manufacturing process monitoring.