Infrared Filters
Photonic crystal made out of metallic screens
(a) Aligned openings of two inductive screens and (b) non-aligned. Similarly for capacitive screens, (c) aligned and (d) non-aligned.
Infrared filters are forms by stacking two-dimensional metallo-dielectric screens in order to achieve three-dimensional structures. Each screen has a resonating behavior at long wavelengths (longer than the feature size) and by stacking them one enhances their transmission or reflection characteristics.
Metal screens with opening are called inductive screens; dielectric screens patched with metal features are called capacitive screens.
Transmission Curves
(a) Simulations for 4 inductive screens at spacing of ¼ resonance wavelength. Thin line: non-aligned, bold: aligned.
(b) Four capacitive screens at spacing of ¼ resonance wavelength. Thin line: non-aligned, bold: aligned.
Haim Grebel, Ph.D.
Director, Electronic Imaging Center
haim.grebel@njit.edu