Single-layer optical bandpass filter technology

Abstract

Resonant periodic surfaces and films enable new functionalities with wide applicability in practical optical systems. Their material sparsity, ease of fabrication, and minimal interface count provide environmental and thermal stability and robustness in applications. Here, we report an experimental bandpass filter fashioned in a single patterned silicon layer on a quartz substrate. Its performance corresponds to bandpass filters requiring 15 traditional Si/SiO(2) thin-film layers. The feasibility of sparse narrowband high-efficiency bandpass filters with extremely wide, flat, and low sidebands is thereby demonstrated. This class of devices is designed with rigorous solutions of Maxwell's equations while engaging the physical principles of resonant waveguide gratings. An experimental filter presented exhibits a transmittance of ∼72%, bandwidth of ∼0.5 nm, and low sidebands spanning ∼100 nm. The proposed technology is integration-friendly and opens doors for further development in various disciplines and spectral regions where thin-film solutions are traditionally applied.

Recent Advances in Resonant Waveguide Gratings

“…Among different implementations, RWGs are an effective way to make such kind of devices with reasonable width and sideband levels for the multiple channels: this need was one of the major driving forces behind the initial research on RWGs in the 1970s . Moreover, RWGs provide thermal stability, robustness, and ease of fabrication, since the performance of a single RWG corresponds to tens of traditional thin‐film layers . A possible way to create a wavelength division (de)multiplexer is to use different gratings to in‐couple, out‐couple, and focus multiple wavelengths at different locations (see Figure f); a small aperture compatible with the beam size of a single mode vertical cavity surface emitting laser can be necessary .…”

“…[28] Moreover, RWGs provide thermal stability, robustness, and ease of fabrication, since the performance of a single RWG corresponds to tens of traditional thin-film layers. [285] A possible way to create a wavelength division (de)multiplexer is to use different gratings to in-couple, out-couple, and focus multiple wavelengths at different locations (see Figure 14f); [190,191,[286][287][288] a small aperture compatible with the beam size of a single mode vertical cavity surface emitting laser can be necessary. [289] Another possibility is to use very thick waveguides in order to benefit from multiple diffraction orders and GMRs.…”

Nanophotonic identification of defects buried in three-dimensional NAND flash memory devices

“…3e for λ = λ 2 and λ 3 , respectively. The fieldintensity distributions involving an enhancement factor of two to four inside the wordline clearly show vertical standingwave patterns that approximate classical TM 3 (λ 2 ) and TM 2 (λ 3 ) guided-mode resonances (GMRs) coupled through a dominant first-order diffraction process [31][32][33] . This GMR-like effect is produced by resonant excitation of the leaky-guided hyperbolic Bloch modes as they are the only propagating optical state in the W-SiO 2 multilayer.…”

Progress in thin film coating on space IR detectors

“…Always to stay on the pixelated filtering, Safran Reosc is also working on photonic filters in collaboration with LAAS-CNRS. More precisely, Zero-contrast grating (ZCG) filters are investigated [4,5]. Such filters don't rely on thin film interferences to build the spectral response, but on guided-mode resonances.…”