A perspective on suspended membrane waveguides for gas sensing applications in mid-infrared spectrum

Abstract Suspended membrane waveguides (SMWs) are crucial for sensing in the mid-infrared (MIR) spectrum due to their exceptional ability to confine light within an ultra-thin dielectric core supported by the membrane, enhancing sensitivity to environmental changes. Properly designed SMWs exhibit minimal optical losses and strong mode confinement, enabling them to maintain high performance even at longer MIR wavelengths, unlike ridge, slot, and subwavelength grating waveguides. This is particularly important for chemical and biological sensing, where precise detection of molecular vibrations in the MIR range is vital. Additionally, the open geometry of suspended membranes allows for better interaction between the guided light and surrounding analytes, leading to improved sensing efficiency and lower limit of detection. These unique characteristics make SMWs especially advantageous for advanced MIR sensing applications.