High-speed tunable multi-bandpass filter for real-time spectral imaging using blue phase liquid crystal etalon

Abstract

We developed a high-speed, electrically tunable multi-bandpass filter using a polymer-stabilized blue-phase liquid crystal etalon and a narrowband multi-bandpass interference filter, for use in real-time multi-spectral imaging systems. We show theoretically that the filter exhibits high-level transmittance (≥ 80%) by using an Ag film as the reflective film used in the etalon. We confirmed that the filter allows for high-speed switching of the transmitted wavelength; the response time is about 1 ms. The filter enables high-transmittance, high-speed spectroscopy. Therefore, high-sensitivity real-time multi-spectral imaging at a frame rate of 60 fps or more can be expected in the future.