Yellow light privacy protection with anti-reflection structure based on photonic band gap principle

Abstract

This paper delves into the one-dimensional photonic crystals (PCs) privacy protection structure (PPS), emphasizing a layered structure with polarization-independent angular response characteristics tailored to meet the need for PPS in various situations. Introducing a specialized design for photonic band gap (PBG), the PPS adheres to the principles of PBG. This design comprises a host structure and an anti-reflection structure carefully selected within the yellow light band (frequency range spans from 530 THz to 510 THz). The given PPS creates an angle selection (AS) window exhibiting transmittance consistently above 0.85 within −29° to 29° while ensuring transmittance drops to 0.1 within the −90° to −46° and 46°–90° range. This arrangement effectively achieves the desired PPS. The effects of the host structure on the four key parameters of refractive index and thickness of the two media on PPS properties were studied in detail. The influence of these parameters mainly involves the transmittance of the visible area, the AS, and the transmittance of the protected area.