High rejection bandpass optical filters based on sub-wavelength metal patch arrays

Abstract

We report the study of a resonant bandpass filter made of a very thin subwavelength metal patch array coupled to a high index dielectric waveguide. The spectral properties of those filters can easily be tuned by playing on the lateral dimensions of the grating. They exhibit high and narrow transmission peaks together with very good rejection of light out of the pass-band and low angular dependance. An experimental demonstration using standard large scale silicon microelectronics processes is presented in the mid infrared spectral range. This concept of filters can easily be scaled throughout the optical spectrum, and can be integrated within focal plane arrays of various imaging technologies, down to visible wavelengths.

Infrared multispectral imaging with silicon-based multiband pass filter and infrared focal plane array

“…2, the filter based on guided-mode resonance (GMR) effects [8] is applied. GMR filters consist of a highindex dielectric waveguide and a subwavelength metal pattern array with lattice symmetry as shown in Fig.…”

Two-mode model for metal-dielectric guided-mode resonance filters

“…Nonetheless, one of the main drawback of these devices is that they are based on membranes, which complicates their fabrication and decreases their mechanical robustness. One solution consists in using a substrate [14]. However, in most of the cases, the introduction of a dissymetry between the top and the bottom interfaces of these filters is to the detriment of its performances.…”

Free-standing guided-mode resonance band-pass filters: from 1D to 2D structures

“…In the case of mid-or far-infrared imaging with extremely low photon flux, the 50% of incident light lost by reflection on polarizing filters is a strong drawback. Several studies have been dedicated to the design of polarization independent filters at normal [14][15][16] and oblique incidences [17][18][19][20].…”