On-chip large homogeneous UV beam shaping via ultrashallow AlOx grating

Chip-based optical beams enable the traditional bio-imaging systems to be less bulky and easier to operate. Beams combining the properties of large homogeneous illumination, high directionality, and steerability are required for high throughput structured illumination microscopy. We present here ultra-shallow etched aluminum oxide (AlOx) integrated gratings that convey an on-chip guided mode into a far field homogeneous UV beam over a 1 mm × 260 μm area. The gratings of footprint 1 mm × 20 μm are designed to operate at an ultraviolet wavelength of 360 nm. Beam directionality and uniformity are assessed using Fourier imaging and fluorescence-based far-field measurements. This work offers a scalable, CMOS-compatible solution for precise spatial light control in bio-sensing and high-resolution microscopy.