Thermo-optical response of photonic crystal cavities operating in the visible

TL;DR

This study investigates the thermo-optical effects in gallium phosphide photonic crystal cavities operating in the visible spectrum, measuring refractive index changes with temperature and demonstrating switching capabilities.

Contribution

It provides the first detailed measurement of the local refractive index of gallium phosphide in tiny volumes over a wide temperature range and explores their use for visible light switching.

Findings

Refractive index of gallium phosphide varies with temperature from 5 K to 300 K.

Photonic crystal cavities enable thermo-optical switching with 13 dB contrast.

Temperature-dependent resonance shifts can be used for tuning photonic devices.

Abstract

In this paper we study thermo-optical effects in gallium phosphite photonic crystal cavities in the visible. By measuring the shift of narrow resonances we derive the temperature dependency of the local refractive index of gallium phosphide in attoliter volumina over a temperature range between 5 K and 300 K at a wavelength of about 605 nm. Additionally, the potential of photonic crystal cavities for thermo-optical switching of visible light is investigated. As an example we demonstrate thermo-optical switching with 13 dB contrast.