Beam Combining of a Tunable Tilted Quantum Cascade Laser Array

Carbon monoxide (CO), with an absorption peak at 4.6 μm, is a critical atmospheric pollutant and health biomarker, driving the need for reliable devices for sensing CO. A tunable quantum cascade laser (QCL) array utilizing tilted waveguides, spanning 4.51–4.61 μm, is reported. By integrating S‐bends, Y‐branches, and a coupler, the array achieves a continuous wave common‐aperture output with high beam quality. Optimizing the beam combining structures enables a single‐channel peak power of up to 80 mW. The proposed QCL array features only a uniform grating prepared through holographic exposure, offering scalability for mass production for gas sensing and medical diagnostics.