Mechanical Tuning of the Terahertz Photonic Bandgap of 3D-Printed One-Dimensional Photonic Crystals

TL;DR

This study demonstrates mechanical tuning of a 3D-printed terahertz photonic crystal's bandgap via compression, achieving a 12 GHz shift, with modeling confirming experimental results.

Contribution

It introduces a novel mechanically tunable terahertz photonic crystal fabricated by single-step stereolithography, with experimental and modeling validation.

Findings

Photonic bandgap centered at 109 GHz shifts under compression.

Maximum observed shift of 12 GHz in the bandgap frequency.

Good agreement between experimental data and optical models.

Abstract

Mechanical tuning of a 3D-printed, polymer-based one-dimensional photonic crystal was demonstrated in the terahertz spectral range. The investigated photonic crystal consists of 13 alternating compact and low-density layers and was fabricated through single-step stereolithography. While the compact layers are entirely polymethacrylate without any intentional internal structures, the low-density layers contain sub-wavelength sized slanted columnar inclusions to allow the mechanical compression in a direction normal to the layer interfaces of the photonic crystal. Terahertz transmission spectroscopy of the photonic crystal was performed in a spectral range from 83 to 124 GHz as a function of the compressive strain. The as-fabricated photonic crystal showed a distinct photonic bandgap centered at 109 GHz, which blue shifted under compressive stress. A maximum shift of 12 GHz in the bandgap center frequency was experimentally demonstrated. Stratified optical models incorporating simple homogeneous and inhomogeneous compression approximations were used to analyze the transmission data. A good agreement between the experimental and model-calculated transmission spectra was found.