Highly Angular Tolerant Transmission Filters for Narrow-Band Image Sensors

A dielectric transmittance filter composed of subwavelength grating sandwiched between two few-layers distributed Bragg reflectors (DBRs) is proposed with the aim being compatible CMOS technology and to be tunable by lithographic means pattern without need thickness changes, in broad spirit metamaterials. The DBR mirrors form a Fabry-Perot (FP) cavity whose resonant frequency can tuned changing effective refractive index cavity, here, tailoring in-plane filling factor grating. structure has been studied designed performing numerical simulations using Fourier Modal Method (FMM). This proves have high angular tolerance up ±30?. feature crucial for evaluating spectral performance narrow-band filters especially so-called Ambient light sensors (ALS). By analyzing distributions band diagram, it found that due coupling FP guided mode inside analogy resonances occurring within multimode periodic waveguides different context.