Room Temperature Operation of a Buried Heterostructure Photonic Crystal Quantum Cascade Laser

TL;DR

This paper presents a novel fabrication method for buried heterostructure photonic crystal quantum cascade lasers that operate at room temperature with high power and good mode control, addressing previous temperature and scalability issues.

Contribution

The authors introduce a deep etching and regrowth fabrication approach enabling room temperature operation and improved thermal management of quantum cascade lasers.

Findings

Lasing operation maintained up to room temperature.

Peak power of 0.88 W at 263 K achieved.

Good photonic mode control with 10% refractive index contrast.

Abstract

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 {\mu}m. 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 550{\mu}m, were identified as slow Bloch photonic crystal modes by means of three-dimensional photonic simulations and measurements.