Inverse design of ultracompact multi-focal optical devices by diffractive neural networks.

We propose an efficient inverse design approach for multifunctional optical elements based on adaptive deep diffractive neural networks (a-DNNs). Specifically, we introduce a-DNNs and design two-layer diffractive devices that can selectively focus incident radiation over two well-separated spectral bands at desired distances. We investigate focusing efficiencies at two wavelengths and achieve targeted spectral line shapes and spatial point-spread functions (PSFs) with optimal focusing efficiency.

Hyperuniform scalar random fields for lensless, multispectral imaging systems: erratum.

We present an erratum to our Letter [Opt. Lett.46, 5360 (2021)10.

Hyperuniform scalar random fields for lensless, multispectral imaging systems.

We propose a novel framework for the systematic design of lensless imaging systems based on the hyperuniform random field solutions of nonlinear reaction-diffusion equations from pattern formation theory. Specifically, we introduce a new class of imaging point-spread functions (PSFs) with enhanced isotropic behavior and controllable sparsity. We investigate PSFs and modulated transfer functions for a number of nonlinear models and demonstrate that two-phase isotropic random fields with hyperuniform disorder are ideally suited to construct imaging PSFs with improved performances compared to PSFs based on Perlin noise.

Phase-modulated axilenses for infrared multiband spectroscopy.

We design and characterize compact phase-modulated axilens devices that combine efficient point focusing and grating selectivity within four-level phase mask configurations. Specifically, we select and characterize in detail two device configurations designed for long-wavelength infrared (LWIR) operation in the $ 6\,\,\unicode{x00B5}{\rm m}\! -\! 12\,\,\unicode{x00B5}{\rm m} $6µm-12µm wavelength range. These devices are ideally suited for monolithic integration atop the substrate layers of infrared focal plane arrays (IR-FPAs) for use in multiband LWIR photodetection.