Projecting light beams with 3D waveguide arrays

TL;DR

This paper demonstrates theoretically and numerically that 3D waveguide arrays can generate complex free-space light beams with structured intensity and phase patterns, offering a compact alternative to traditional spatial light modulators.

Contribution

It introduces a novel approach to produce complex optical beams directly from engineered 3D waveguide arrays, bypassing traditional modulators and enabling integrated beam shaping.

Findings

Achieves orbital angular momentum in projected beams

Produces elaborate intensity and phase patterns with singularities

Shows potential for integrated complex beam generation

Abstract

Free-space light beams with complex intensity patterns, or non-trivial phase structure, are demanded in diverse fields, ranging from classical and quantum optical communications, to manipulation and imaging of microparticles and cells. Static or dynamic spatial light modulators, acting on phase or intensity of an incoming light wave, are the conventional choices to produce beams with such non-trivial characteristics. However, interfacing these devices with optical fibers or integrated optical circuits often requires difficult alignment or cumbersome optical setups. Here we explore theoretically and with numerical simulations the potentialities of directly using the output of engineered three-dimensional waveguide arrays, illuminated with linearly polarized light, to project light beams with peculiar structures. We investigate through a collection of illustrative configurations the far field distribution, showing the possibility to achieve orbital angular momentum, or to produce elaborate intensity or phase patterns with several singularity points. We also simulate the propagation of the projected beam, showing the possibility to concentrate light. We note that these devices should be at reach of current technology, thus perspectives are open for the generation of complex free-space optical beams from integrated waveguide circuits.