Coherent LIDAR range sensing by use of spatial-spectral holography

Abstract

We introduce a new approach to coherent LIDAR remote sensing by utilizing a quantum-optical, parallel sensor based on spatial-spectral holography (SSH) in a cryogenically cooled inhomogeneously-broadened absorber (IBA) crystal that is used to sense the LIDAR returns and perform the front-end range-correlation signal processing. This SSH sensor increases the LIDAR system sensitivity through range-correlation gain before detection. This approach permits the use of high-power, noisy, CW lasers as ranging waveforms in LIDAR systems instead of the highly stabilized, injection seeded and amplified pulsed laser sources required by most coherent LIDAR systems. The capabilities of the IBA media for many 10s of GHz bandwidth and sub-MHz resolution, while using either a coded waveform or just a high-power, noisy laser with a broad linewidth (e.g. a random noise LIDAR) may enable a new generation of improved LIDAR sensors and processors. Preliminary experimental demonstrations of LIDAR range detection and signal processing for random noise and chirped transmitted waveforms are presented.