Development of a novel laser system for the CZMIL lidar

Abstract

The Coastal Zone Mapping and Imaging Lidar (CZMIL) system¹ aims to expand bathymetric lidar performance in shallow water conditions, where high spatial and temporal data resolutions are required. This must be achieved without sacrificing performance in deep water. Very high frequency data collection (as high as 70KHz) utilizing a hybrid flash-point lidar approach is utilized, which places high demands on the transmitted laser beam, namely high pulse power with short duration with very high fidelity beam characteristics. To meet these requirements, we have developed a compact, high-power, short pulse length, high repetition rate laser with beam quality acceptable for use with the hybrid lidar approach employed in CZMIL. The short pulse length is achieved using a CW-pumped Q-switched oscillator, and the required power is achieved by using multiple amplifiers employing fiber coupled, CW end-pumped Nd:YVO₄ crystals prior to doubling the 1064 nm beam. The resulting output power is ~ 30W at 10 kHz with a pulse length of < 2.5 ns FWHM at 532 nm and ~ 20W of residual power at 1064 nm.