Surface emitting multi-wavelength array of single frequency quantum cascade lasers

We present a surface emitting laser array design based on distributed Bragg reflectors together with a second order extractor, providing a deterministic mode selection mechanism. The technology is implemented as a buried heterostructure compatible with continuous-wave operation and low dissipation. A proof of principle featured 10 regularly spaced single mode devices with a coverage of 175 cm⁻¹ in the 8–10 μm wavelength range and milliwatt output powers with a far-field pattern full-width half-maximum of 8.3° in the longitudinal direction