Design of multispectral remote sensing filter film and research on film thickness monitoring technology

There are numerous applications for multispectral filter film, including remote sensing detection, medical treatment, and military camouflage recognition. The process of preparing it is complex, which has resulted in a high price tag and low yield. We use electron beam evaporation to create five-spectral-band filter films between 380 and 900 nm using Ta2O5 and SiO2. Multispectral filter films with different bandwidths are designed using multiple methods derived from thin-film theory. Using the characteristics of each channel spectrum, three methods of monitoring film thickness were combined to prepare each channel: crystal oscillator monitoring, back-reflection monitoring, and optical transmittance monitoring. Using mechanical masks to prepare each channel individually, the transmittance over the passband is greater than 95%, and the spectral rectangle meets the requirements of applications.