Compact 2-Micron Transmitter for Remote Sensing Applications

In this Phase II effort we propose to work with NASA to extend the Phase I achievements, which focused on design and development of very compact master and long-pulse slave oscillator lasers operating near 2.05 um wavelength. Beyond Photonics LLC's "SWIFT" laser was matured and largely productized, with an initial unit delivered in Phase I. In parallel, conceptual and preliminary design and risk-reduction of a very compact short-cavity Tm,Ho:YLF Q-switched laser was achieved, which will be extended significantly in Phase II and result in a robust injection-seeded, actively pulse-stretched prototype. The compact transmitter will include a "nano-SWIFT" that will have size and weight comparable to a butterfly-packaged DFB diode laser but with far better frequency stability and higher power. In Phase II we will demonstrate output characteristics of 32 mJ, 100 Hz PRF, and 300-500 ns pulse durations from this compact robust injection-seeded transmitter. This moderate-PRF moderate-energy transmitter will be immediately suitable for 3D winds from ground and airborne platforms and with continued TRL advancement eventually space platforms. The transmitter will be capable of efficient operation at >4 W average power at lower pulse energies and higher PRFs (e.g.. 1 -4 kHz) which is suitable for IPDA spectroscopy and hard target measurement lidar systems operating from space (following an appropriate engineering and qualification effort) using either coherent or direct detection with state-of-the-art low-noise direct detectors. The overarching objective of the proposed effort is to develop compact, efficient, and reliable pulsed and cw lasers and lidar transmitters for future NASA missions. Specifically, we address needs described for 3D winds, atmospheric CO2 and H20 concentration sensing in the 2.05 um region; but we also recognize that such innovations can be readily applied to transmitter laser operation at other IR and SWIR wavelengths and associated instruments.