Ring-Cavity Surface Emitting QCL with Higher Power and Excellent Beam Quality

Abstract

Researchers at the University of Central Florida have developed ring-cavity surface-emitting quantum cascade lasers (RCSE-QCLs) that are concentrically nested to combine power, coupled to ensure coherent emission, and phase controlled with integrated optical delays to engineer the beam profile. This novel method obtains high-power continuous-wave coherent laser radiation at wavelengths from 4 to 20 micrometers and provides a new design approach of a power-scalable, chip-based, high-power, single aperture RSCE-QCL with outstanding beam quality (M2 < 1.2) at infrared wavelengths. This device's output power is over 15W continuous-waves through a single aperture.

RSCE-QCLs provide large exit apertures with low power densities and stabilized emission wavelengths via second-order distributed feedback, from surface gratings that double as output couplers. Generally, RSCE-QCLs enable wafer-level fabrication and testing, which reduces piece work and handling, which in turn lowers manufacturing costs. Unlike RSCE-QCLs that emit non-Gaussian beams, nested concentric RSCE-QCLs emit more uniform radiation patterns.

Technical Details

This RSCE-QCL comprises a ring-shaped active region with first and second opposing facets, with at least one of the facets defining a radiation-emitting facet and is aligned with a ring-shaped phase shifter with a spiraled surface. A substrate is located adjacent to the ring-shaped active region and opposite of the emitting facet, and a ring-shaped phase shifter is located on the radiation emitting facet the ring-shaped active region.

Benefit

Market Application