Phase-locked array of quantum cascade lasers with an intracavity spatial filter

TL;DR

This paper presents a novel phase-locked array of quantum cascade lasers using an intracavity Talbot cavity, achieving stable in-phase operation, improved beam quality, and increased power output for mid-infrared applications.

Contribution

Introduces a new phase-locked quantum cascade laser array with an integrated Talbot cavity, enhancing power and beam shaping capabilities with a simple fabrication process.

Findings

Stable in-phase operation from threshold to full power

Beam divergence smaller than single lasers

Maximum power about 3-5 times that of single lasers

Abstract

Phase-locking an array of quantum cascade lasers is an effective way to achieve higher output power and beam shaping. In this article, based on Talbot effect, we show a new-type phase-locked array of mid-infrared quantum cascade lasers with an integrated spatial- filtering Talbot cavity. All the arrays show stable in-phase operation from the threshold current to full power current. The beam divergence of the array device is smaller than that of a single-ridge laser. We use the multi-slit Fraunhofer diffraction mode to interpret the far-field radiation profile and give a solution to get better beam quality. The maximum power is just about 5 times that of a single-ridge laser for eleven-laser array device and 3 times for seven-laser array device. Considering the great modal selection ability, simple fabricating process and the potential for achieving better beam quality and smaller cavity loss, this new-type phase-locked array may be a hopeful and elegant solution to get high power or beam shaping.