On-chip wavelength-programmed deep-ultraviolet laser array

Abstract Monolithic laser arrays represent a foundational technology for chip-scale photonics, offering precise control and multiplexing of light to advance fields such as integrated optics and quantum information processing. While such arrays have been successfully realized in the visible and infrared regimes over the past decades, developing on-chip deep ultraviolet (DUV) laser arrays has remained a significant challenge. Here, we overcome this barrier by demonstrating a DUV laser array with deterministic, emitter-by-emitter wavelength programmability, achieved through a ridge-width-engineering approach. By tailoring the lateral dimensions of ridge waveguides, we deliberately modulate optical field confinement, which in turn adjusts the effective modal refractive index and shifts the cavity resonance wavelength for each individual laser emitter. Combined with smooth, vertical cavity facets, this strategy enables room-temperature optically-pumped DUV lasing across a programmable range from 252 to 259 nm on a single integrated chip. This work demonstrates an optically-pumped wavelength-programmed DUV laser array on a single chip, providing a useful proof-of-concept toward future integrated DUV photonic systems and compact multi-wavelength ultraviolet light sources.