Near index matching enables solid diffractive optical element fabrication via additive manufacturing

Abstract

Diffractive optical elements (DOEs) have a wide range of applications in optics and photonics, thanks to their capability to perform complex wavefront shaping in a compact form. However, widespread applicability of DOEs is still limited, because existing fabrication methods are cumbersome and expensive. Here, we present a simple and cost-effective fabrication approach for solid, high-performance DOEs. The method is based on conjugating two nearly refractive index-matched solidifiable transparent materials. The index matching allows for extreme scaling up of the elements in the axial dimension, which enables simple fabrication of a template using commercially available 3D printing at tens-of-micrometer resolution. We demonstrated the approach by fabricating and using DOEs serving as microlens arrays, vortex plates, including for highly sensitive applications such as vector beam generation and super-resolution microscopy using MINSTED, and phase-masks for three-dimensional single-molecule localization microscopy. Beyond the advantage of making DOEs widely accessible by drastically simplifying their production, the method also overcomes difficulties faced by existing methods in fabricating highly complex elements, such as high-order vortex plates, and spectrum-encoding phase masks for microscopy.

A perspective on the artificial intelligence’s transformative role in advancing diffractive optics

“… 5 This demands the application of sophisticated algorithms and optimization techniques, often coupled with advanced fabrication methods like lithography or laser writing. 6 Furthermore, diffractive optics is susceptible to environmental factors such as temperature fluctuations and mechanical strains, which can induce undesired aberrations and compromise performance. 7 Another obstacle arises from the limited spectral bandwidth of diffractive elements, constraining their effectiveness in broadband optical systems.…”

Compact hyperspectral imaging of extreme-depth-of-field diffractive lenses based on spatial–spectral sparse deep learning

“…Building upon the compressive sensing theory 29,30 , a number of scan-less [31][32][33][34][35] HI systems has been successively proposed that can reconstruct a complete spectral image snapshot without the need for scanning, but with a coded aperture. Owing to the imaging solution and bandwidth limitations of the aperture as well as recent advancements in diffractive optical elements (DOEs) [36][37][38][39][40][41] , there has been a growing interest in incorporating coding capabilities into a single DOE. Achromatic spectral imaging in a compact form can be achieved using a single DOE 42 , overcoming the integration and broad-bandwidth challenges associated with multiple optical element sets.…”