Room temperature surface emission on large-area photonic crystal quantum cascade lasers

Abstract

We design and fabricate large-area (1.1 mm × 1.1 mm) photonic crystal quantum cascade lasers, enabling single-mode (wavelength ∼ 8.5 µm) surface emission at room temperature, with a maximum peak power up to 176 mW. The beam divergence is <1∘ and with no side-lobes. Moreover, by introducing asymmetry into the photonic crystal pillar shape, a single-lobed far-field pattern is realized. The photonic band structure is measured with high spectral (0.72 cm−1) and angular (0.1°) resolution by using the photonic crystal quantum cascade laser itself as a detector.