Surface-Emitting, Monolithic Beam-Combined Mid-Wave IR Quantum Cascade Lasers

Period of Performance: 08/15/2013 - 03/15/2014


Phase 1 STTR

Recipient Firm

Intraband LLC
200 N. Prospect Ave. Array
Madison, WI 53726
Principal Investigator
Firm POC

Research Institution

University of Wisconsin, Madison
2100 Main Street
Madison, WI 53706
Institution POC


The technical objectives of this proposal are: (1) design a grating-coupled surface-emitting (GCSE) active-photonic-crystal (APC) 4.6 micron-emitting quantum-cascade laser (QCL) to deliver 15 W diffraction-limited CW power in the main lobe of the far-field beam pattern; (2) design a GCSE-APC QCL structure with monolithic aperture-filling optical elements for obtaining close to 90 % of the surface-emitted power into the main lobe of the far-field beam pattern; and (3) design a GCSE-APC QCL structure employing second-order gratings with chirped period for increasing the light-outcoupling efficiency and the device wallplug efficiency. Step-taper-active (STA) QCLs will be used in the design since they suppress carrier leakage out of the QCL active regions, resulting in electro-optic characteristics much less temperature sensitive than for conventional QCLs; thus, allowing for significant increases in CW power and wallplug efficiency. The design will be for APC devices of built-in index step an order of magnitude higher than for conventional APC-QCL as to achieve stable-beam operation in CW operation to high coherent powers with high wallplug efficiency. For 4.6 micron-emitting devices the design will be for usable CW powers as high as 20 W, delivered in diffraction-limited beams.