Liquid deposition photolithography for submicrometer resolution three-dimensional index structuring with large throughput

Photonic devices increasingly require three-dimensional control of refractive index,but existing fabrication methods such as femtosecond micromachining,multilayer lithography and bulk diffusion can only address a select scale range,are often limited in complexity or thickness and have low throughput.We introduce a new fabrication method and polymeric material that can efficiently create mm^(3) optical devices with programmable,gradient index of refraction with arbitrary feature size.Index contrast of 0.1 is demonstrated,which is 100 times larger than femtosecond micromachining,and 20 times larger than commercial holographic photopolymers.This is achieved by repetitive microfluidic layering of a self-developing photopolymer structured by projection lithography.The process has the unusual property that total fabrication time for a fixed thickness decreases with the number of layers,enabling fabrication 10^(5) faster than femtosecond micromachining.We demonstrate the process by sequentially writing 100 layers to fabricate a mm thick waveguide array.