We present our latest results on the development of high power, high efficiency room temperature quantum cascade lasers. Strain-balanced, InP-based quantum cascade structures, designed for light emission at 4.6 μm using a new non-resonant extraction design approach, were grown by molecular beam epitaxy and processed as buried heterostructure lasers. Maximum single-ended continuous-wave optical power of 3 W was obtained at 293 K for devices with stripe dimensions of 5 mm by 11.6 μm mounted on diamond submounts. Corresponding maximum wallplug efficiency and threshold current density were measured to be 12.7% and 0.86 kA/cm². 7 mm-long, 8.5 μm-wide devices mounted on aluminum nitride submounts with optimized reflectivity coatings on the output facet emitted 2.9 W under the same conditions and 1.2 W in uncooled pulsed operation. Leveraging this research, we developed fully packaged, air-cooled, table-top turn-key laser systems delivering in excess of 2 W of collimated continuous-wave radiation. The high performance and level of device integration make these quantum cascade lasers the primary choice for various defense and security applications, including directional infrared countermeasures, mid-wave infrared illuminators and free space optical communications.

Date Published: 25 September 2009
PDF: 9 pages
Proc. SPIE 7483, Technologies for Optical Countermeasures VI, 74830D (25 September 2009); doi: 10.1117/12.830228

Published in SPIE Proceedings Vol. 7483:
Technologies for Optical Countermeasures VI
David H. Titterton; Mark A. Richardson, Editor(s)