Optical Gas Sensors

Abstract

Miniature and highly efficient optical-based gas sensors have gained enormous consideration over the last few years. Materials based on the group-IV elements, namely silicon, germanium and their compounds, are deemed to be the potential candidates for the optical gas sensors. Optical gas sensors based on these materials offer appreciable sensitivity and high-density integration. Basically, these sensors paved the path for the flexible applications areas, namely internet of things (IoT), point-of-care testing, information and communication technology, etc. because of their potential candidature for being integrated with the several other photonic or electronic devices for on-chip signal processing and communication. Herein, we review optical gas sensors and discuss their basic principles, applications, recent advancement in the devices, etc. Gas concentrations can be easily detected and measured utilizing the characteristic optical absorption of gas species. This detection is crucial both for interpretation and observing of a wider range of phenomena extended from industrial practices to overall environmental change. Based on the findings, this review extends over a comprehensive overview of plethora of individual gas detection techniques, namely non-dispersive infrared, spectro-photometry, tunable diode laser spectroscopy and photo acoustic spectroscopy. This article focalizes over the discussion of the basic principle of the techniques introduced, their latest advancements and performance constraints, etc.

Diffusion flames and a semi-empirical method for estimating the distribution of hydrogen molecules in propane flames

“…V. Mishra and S. Rashmi [26] considering methods for determining gas concentrations in general, argued that the use of methods related to optical absorption offers several advantages that alternative technologies cannot provide. Since measurements are based on a fundamental physical property of the molecule under study, there are ways to avoid some of the error mechanisms present in other technologies, including drift, lack of selectivity, and changes in sensitivity from experiment to experiment.…”

Overview of Gas Sensors Focusing on Chemoresistive Ones for Cancer Detection

“…For instance, many gases exhibit high absorption mainly in the ultraviolet-visible (200-400 nm, due to electronic transitions), near-infrared (700 nm to 2.5 µm, due to first harmonic molecular vibrations and rotations), and midinfrared (2.5-14 µm, due to fundamental molecular vibration and rotation) ranges of the electromagnetic spectrum, with a unique set of absorption bands (Figure 4). Therefore, optical sensors must take advantage of the wavelength and intensity of these bands to be able to detect the analytes and quantify their concentrations [18,38]. Other sensors detect, instead, the fluorescence light emission of the analytes or their light scattering properties, but because of their less common use, they are not reviewed here.…”

Sol-Gel Production of Semiconductor Metal Oxides for Gas Sensor Applications

“…The primary types include optical, electrochemical, and electrical sensors, as demonstrated in an overview of gas sensor classification depicted in Figure 1. Optical gas sensors use light to detect the presence of gases by measuring changes in light absorption or scattering [33,34]. In contrast, electrochemical gas sensors use a chemical reaction to produce an electrical signal that can be measured and interpreted as the concentration of gas [35].…”