SBIR-STTR Award

High-power solid state lasers using different active media have emerged as critical components in a variety of military systems. These lasers are efficiently and reliably pumped by diode laser arrays, but the poor and uneconomical scalability of output power and high manufacturing cost of linear, edge emitting diode arrays pose a serious impediment to wide application, particularly where very high total powers are required. There is little prospect that conventional approaches to laser design can result in cost reduction of the required magnitude. We propose to develop diode arrays using two technology elements that are complementary and compatible with each other to achieve the required performance and manufacturing scalability objectives. The first technology element or these arrays are massively parallel surface emitting diodes using monolithic beam deflectors to permit wafer-scale diode fabrication and integration with wafer-scale optics and coolers, which enables manufacturing process scalability for high-power applications and greatly reduces diode fabrication and packaging cost. The second technology element is diode lasers with gratings designed to generate lower lateral beam divergence, therefore higher optical brightness per emitter than conventional designs.. These features will allow very efficient optical coupling into the end-facets of eye-safe solid-state lasers.

Keywords:
Highly Scalable Spectrally-Narrowed Surface-Emitting Laser Arrays, Macro-Channel Cooling, Eye-Safe Er-Doped Solid-State Lasers, Monolithic Beam Deflector Diode Array, Laser Di

Diode pumped lasers have military applications including directed energy weaponry, target designation, and LADAR imaging, as well as many civilian uses. Unfortunately, standard lasers generate beams near 1000 nm, which are very hazardous to the eyes of friendly and noncombatant personnel, which severely restricts their use. Erbium doped lasers generate much safer beams in the 1500 nm band, but are not yet practical for directed energy because the broad spectra of existing pump diode arrays are too broad for efficient absorption, and because existing pumps are too expensive. QPC has demonstrated, in Phase I, pump lasers using a novel laser architecture called HPSEL (High Power Surface Emitting Laser) which provides much narrower, strongly absorbed pump beams which are strongly absorbed in Erbium, resulting in much higher laser efficiency and power. HPSEL pump arrays emit in the vertical direction and can be fabricated and tested at wafer level much more cheaply than conventional, edge-emitting arrays.

Keywords:
Eye-Safe Lasers, Directed Energy, Erbium, Range Finding, Low Cost, Collateral Damage