On-chip spectroscopy with thermally-tuned high-Q photonic crystal cavities

TL;DR

This paper demonstrates a compact on-chip spectrometer using thermally-tuned high-Q photonic crystal cavities, capable of high-resolution chemical detection and discrimination of hazardous gases.

Contribution

It introduces a novel chip-scale spectrometer based on high-Q photonic crystal cavities that can perform high-resolution spectroscopy on a chip.

Findings

Successfully measured absorption spectra of acetylene and hydrogen cyanide

Demonstrated discrimination between two chemical species in the same spectral region

Showed potential for developing portable chemical sensors

Abstract

Spectroscopic methods are a sensitive way to determine the chemical composition of potentially hazardous materials. Here, we demonstrate that thermally-tuned high-Q photonic crystal cavities can be used as a compact high-resolution on-chip spectrometer. We have used such a chip-scale spectrometer to measure the absorption spectra of both acetylene and hydrogen cyanide in the 1550 nm spectral band, and show that we can discriminate between the two chemical species even though the two materials have spectral features in the same spectral region. Our results pave the way for the development of chip-size chemical sensors that can detect toxic substances.