Spatial light modulator based holographic fabrication of 3D spatially varying photonic crystal templates

Abstract

In this work, we present holographic fabrication of spatially varying photonic crystal templates of gradient index structures in photosensitized polymer using the interference of multiple beams with specified phases generated by an engineered grayscale phase patterns displayed on a phase only spatial light modulator (SLM) in conjunction with a 4f imaging system. Simple spatially varying 3D structures are fabricated by the interference of four 1 st order beams with desired phases plus a central 0 th order beam generated by pixel-by-pixel assignment of the gray levels of cells and supercells within the phase pattern displayed on the SLM. Additionally, a low order simple gradient or vortex phase can be added to a multi-beam-generating phase pattern to also create an angularly varying 3D structure. We also demonstrate 2D and 3D spatially variant wave fields that can be used to fabricate photonic crystal templates in photoresist with variation in lattice orientation and spacing using interference of modified beams with specified phases produced by an engineered phase pattern displayed on a SLM. With control of the phases of interfering beams using an SLM, holographic fabrication of spatially varying photonic lattices becomes possible.