Interferometric-Based SPR Sensors

Different kinds of interferometric optical sensors are introduced here, along with their applications and operational principles. Interferometric sensors can be broken down into several broad types, including the Mach–Zehnder interferometer, the Michelson interferometer, the Sagnac loop interferometer, and the Fabry–Perot interferometer. Physical characteristics such as temperature, pressure, stress, strain, etc., can all be detected with the use of these sensors. An interferometer uses the interference that is produced by the divergence of two beams to function. This necessitates the inclusion of beam splitting and beam combining elements in the interferometric setup, which requires designing one of the optical channels so that it adapts to environmental changes. Interferometric signals can be used to learn about the target throughout time and across several wavelengths, intensities, phases, frequencies, and bandwidths. These alterations can improve the device’s functionality by expanding its dynamic range, sensitivity, and accuracy. Miniaturizing fiber optic interferometers is essential for the current trend of micro-scale applications. To do this, conventionally large fiber optic components like combiners, beam splitters, and objective lenses are being replaced with new, smaller fiber devices that function on fiber scales. SPR sensing provides a more accurate and exact measurement of the refractive index of a substance close to metal than traditional optical interferometers. As the need for chemical and biological compound detection and analysis increases in important areas like medicine, environmental monitoring, biotechnology, pharmaceuticals, and food monitoring, SPR sensor technology holds great promise. The chapter concludes with a discussion of the structure, content, performance, and application of several interferometric SPR sensors.