Due to their unique diffractive properties, Bessel beams have contributed to a variety of important advances and applications, including multiplane optical trapping, reduced scattering and increased depth of field microscopy, improved laser corneal surgery, and adaptive free-space communications. Recent work has turned toward generation of Bessel beams using compact form factors, including spatial light modulators, Dammann gratings, and metasurfaces. However, these demonstrations do not provide full on-chip integration, and most are fundamentally limited to static beam formation.
In this work, integrated optical phased arrays, which manipulate and dynamically steer light, are proposed and demonstrated for the first time as a method for generating quasi-Bessel beams in a fully integrated, compact-form-factor system . First, the phase and amplitude distributions necessary for generating phased-array-based Bessel-Gauss beams are derived analogously to bulk-optics Bessel implementations. Next, a splitter-tree-based CMOS- compatible phased array architecture is developed to passively encode arbitrary phase and amplitude feeding of the array -- necessary for Bessel-Gauss-beam generation. Finally, the developed theory and system architecture are utilized to demonstrate a 0.64 mm × 0.65 mm aperture integrated phased array that generates a quasi-one-dimensional Bessel-Gauss beam with a ~14 mm Bessel length and ~30 µm power FWHM.