Near-infrared tuneable filter based on polymer dispersed liquid crystals

Dynamic filtering is crucial in various applications, including imaging, communication, and biological detection. With advancements in micro-nano device fabrication, there is a growing demand for enhanced filtering performance. This paper presents a near-infrared single-wavelength tuneable filter that utilizes polymer-dispersed liquid crystal combined with a Fabry–Perot resonant cavity. The device achieves a transmittance of 99% at 927 nm with a 24 nm full width at half maximum. Utilizing the electro-optical tuneable properties of dielectric layer, the transmission wavelength can be tuned from 913 to 969 nm by altering external voltage to it, resulting in a wavelength shift of 56 nm while maintaining high transmittance. This structure provides a reference for the dynamic control of light sensors and near-infrared dynamic imaging.