Dual Optical Comb LWIR Source and Sensor
Technical Report,28 Sep 2015,28 Sep 2017
Physical Sciences Inc. Andover United States
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In this program we developed a compact dual-optical frequency comb OFC sensor for standoff detection of national security relevant compounds. These compounds are primarily solids at room temperature and consequently have low vapor pressure. In realistic application scenarios these materials are found on common diffusely reflective Because the target materials have their strongest spectral signatures in the longwave infrared LWIR regime, our OFC sources are based on dispersion compensated quantum cascade lasers QCLs in the 8 to 12 micron regime. The lasers emit about 1W of optical power under cw operation near room temperature and produce combs with optical bandwidths exceeding 100 wavenumbers. We developed processing algorithms for reducing the high bandwidth multi-heterodyne data stream into the desired spectral information with up to 0.3 cm-1 resolution and optimizing the signal to noise ratio. Finally, we tested a prototype dual-comb system against diffusely scattering surfaces at standoff distances up to 1 meter and demonstrated spectral discrimination at the few microgram mass loading level, a relevant metric for national security needs.
- Optical Detection and Detectors