Development Of Microstructure Narrowband Filter

Multispectral imaging technology is advanced in the field of target detection,and is tending to more spectral channels,more integrated,smaller and lighter direction development,so the multichannel microstructure narrowband filter has be a hotspot of research.However,development of microstructure narrowband filter also has some limitations,such as the low channel spectral transmittance,the low degree of miniaturization and preparation.So,it is necessary to further explore preparation methods and preparation technology of microstructure narrowband filter.In this paper,the design and preparation technology of microstructure narrowband filter are studied,and three filters with different center wavelength are designed based on concepts of Fabry-Perot principle;microstructure units are fabricated by technique of photochemical mask separation;the narrowband filters are fabricated by PECVD technology,the reproducibility of thin film are researched.The results show that:(1)For conventional All-Dielectric Single-Cavity F-P thin film filter,the film stack G/(HL)22mH(LH)2/A of the high-index cavity has the best design results,good peak transmittance and pass band width.It is easy to be prepared in the actual situation because it has less layers and thinner total thickness.(2)The narrowband filters with the center wavelength at 480nm,520nm and 590nm are fabricated by PECVD technology.The peak transmittances of these filers are 83.85%respectively,83.49%and 90.38%,half the width of the band are 33nm,50nm and 49nm,respectively.(3)Through the study of reproducibility of linear array microstructure,it gets that thin film deposition rate,thickness and the depth of the microstructure greatly influence the reproducibility.On this basis,the technology of reproducibility is optimized.Combined with design results of film stack,the monolayer films of SiOx and SiNx with good reproducibility are prepared with optimal process parameters,on the substrate of a mask with the thickness of 1?m.The gradient of mask's cross section is 1.4 and 1.2,respectively.(4)Microstructure narrowband filters with an area of 50?m×50?m for each microstructure unit are fabricated by combining PECVD and photochemical mask separation techniques.It has a neat edge,clear dividing line and has good spectral performance.Peak transmittance rates from 80%to 90%,FWHM of the three bands are among 30 to 50 nm,and the location of the center wavelength offset remains within 4nm.