Direct (3+1)D laser writing of graded-index optical elements

TL;DR

This paper introduces a novel (3+1)D laser writing technique for fabricating graded-index optical elements in a single step, enabling precise control of optical properties for advanced photonic devices.

Contribution

The authors present a new single-step additive manufacturing method using (3+1)D laser writing to create graded-index optical components with customizable profiles.

Findings

Successfully fabricated graded-index profiles using a commercial printer and photoresist.

Demonstrated volume holograms with angular and peristrophic multiplexing.

Controlled propagating modes in waveguides by tuning (3+1)D-printed parameters.

Abstract

We propose single-step additive fabrication of graded-index optical elements by introducing the light exposure as the additional dimension to three-dimensional (3D) laser writing, hence (3+1)D writing. We use a commercial printer and photoresist to realize the proposed single step fabrication method that can be swiftly adopted for research and engineering. After presenting the characterization of the graded-index profiles via basic structures, we demonstrate two different optical devices: volume holograms that are superimposed using angular and peristrophic multiplexing, and optical waveguides with well-defined refractive index profiles. In the latter, we precisely control the propagating modes via tuning the (3+1)D-printed waveguide parameters and report step-index and graded-index core-cladding transitions.