Room temperature operation of a deep etched buried heterostructure photonic crystal quantum cascade laser

High power single mode quantum cascade lasers with a narrow far field are important for several applications including surgery or military countermeasure. Existing technologies suffer from drawbacks such as operation temperature and scalability. In this paper we introduce a fabrication approach that potentially solves simultaneously these remaining limitations. We demonstrate and characterize deep etched, buried photonic crystal quantum cascade lasers emitting around a wavelength of 8.5 μm. The active region was dry etched before being regrown with semi‐insulating Fe:InP. This fabrication strategy results in a refractive index contrast of 10% allowing good photonic mode control, and simultaneously provides good thermal extraction during operation. Single mode emission with narrow far field pattern and peak powers up to 0.88 W at 263 K were recorded from the facet of the photonic crystal laser, and lasing operation was maintained up to room temperature. The lasing modes emitted from square photonic crystal mesas with a side length of 550μm, were identified as slow Bloch photonic crystal modes by means of three‐dimensional photonic simulations and measurements. This paper presents the demonstration and characterization of deep etched square lattice photonic crystal quantum cascade laser emitting at around 8.5 μm under room temperature operation. The observed lasing modes were identified as slow Bloch photonic modes of a 550 μm side square photonic crystal mesa. The measured emission showed an output peak power of 0.88 W at 263 K with single mode behavior and narrow far field pattern, from a facet.