High-brightness tapered quantum cascade lasers

摘要

An index-guided tapered quantum cascade laser emitting near 9.5 μm with sloped sidewalls and no anti-reflection coating is presented, and the performance for devices with taper half-angles of 1° and 2° is investigated. The 1° device delivers up to 2.5 W of peak optical power at room temperature with beam quality-factor M2 = 2.08, while the two-degree device outputs 3.8 W with M2 = 2.25 for a maximum brightness of 1.87 MW cm-2 sr-1.