Vanadium oxide thin films for optical readout-based thermal imager

In this study, optical characterization of vanadium oxide (VOx) thin film is performed using a variable angle spectroscopic ellipsometer (VASE). The characterization is performed at four different room temperatures, 25.5-28.5 degrees C, in steps of 1 degrees C. The best fitting results of the ellipsometric parameters phi and Delta are obtained by using a GenOsc layer with the Lorentz oscillator. Four different thermo-optic coefficients (TOCs) are obtained from the modelled data. The TOC value with the least extinction coefficient is chosen, which occurs at 26.5 degrees C. The effect of the TOC value on shifting the Fabry-Perot cavity filter (FPCF) tuning frequency is examined on all designs (2, 4, and 6 stacks) to determine the sensitivity of the FPCF sensor in scene temperature variations. We verify the performance of the sensor as a long-wave infrared radiation absorber and as a visible light band-pass filter. This sensor is designed to have a low thermal conductivity and a low mechanical stress.