High-Brightness Tapered Quantum Cascade Lasers

An index-guided tapered quantum cascade laser emitting near 9.5 mu m with sloped sidewalls and no anti-reflection coating is presented, and the performance for devices with taper half-angles of 1 degrees and 2 degrees is investigated. The 1 degrees device delivers up to 2.5 W of peak optical power at room temperature with beam quality-factor M-2 = 2.08, while the two-degree device outputs 3.8 W with M-2 = 2.25 for a maximum brightness of 1.87 MW cm(-2) sr(-1). (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4791557]