Holographically fabricated out-of-plane blazed gratings and channel waveguides in silica for integrated free-space beam delivery.

Abstract

Grating couplers are widely used in integrated optics to generate free-space beams and facilitate localized interactions with systems such as atom or ion traps. However, etched devices often exhibit small-scale inconsistencies; exacerbated by the high index contrast of the devices, this can lead to phase errors, limiting devices to a sub-millimeter scale. Here we present the first demonstration, to our knowledge, of tilted, out-of-plane blazed gratings in planar silica fabricated by UV inscription using a 213 nm laser. Our devices deliver collimated and focusing beams into free space from a waveguide input without the need for additional optics such as beam expanders.