Integrated Nanophotonic Waveguide-Based Devices for IR and Raman Gas Spectroscopy

On-chip devices for absorption spectroscopy and Raman spectroscopy have been developing rapidly in the last few years, triggered by the growing availability of compact and affordable tunable lasers, detectors, and on-chip spectrometers. Material processing that is compatible with mass production has been proven to be capable of long low-loss waveguides of sophisticated designs, which are indispensable for high-light-analyte interactions. Sensitivity and selectivity have been further improved by the development of sorbent cladding. In this review, we discuss the latest advances and challenges in the field of waveguide-enhanced Raman spectroscopy (WERS) and waveguide infrared absorption spectroscopy (WIRAS). The development of integrated light sources and detectors toward miniaturization will be presented, together with the recent advances on waveguides and cladding to improve sensitivity. The latest reports on gas-sensing applications and main configurations for WERS and WIRAS will be described, and the most relevant figures of merit and limitations of different sensor realizations summarized.

Automated summary

In recent years, on-chip devices for absorption spectroscopy and Raman spectroscopy have experienced rapid development due to the widespread availability of compact and affordable tunable lasers, detectors, and on-chip spectrometers. Material processing compatible with mass production has enabled the production of long low-loss waveguides of sophisticated designs to enhance high-light-analyte interactions, while sensitivity and selectivity have been further improved through the development of sorbent cladding. Studies on waveguide-enhanced Raman spectroscopy (WERS) and waveguide infrared absorption spectroscopy (WIRAS) have focused on advancements in integrated light sources and detectors for miniaturization, recent developments in waveguides and cladding to enhance sensitivity, and gas-sensing applications and main configurations, as well as summarizing relevant figures of merit and limitations of different sensor implementations.