Miniature Spectroscopes with Two-Dimensional Guided-Mode Resonant Metal Grating Filters Integrated on a Photodiode Array

Abstract

A small spectroscope with 25 color sensors was fabricated by combining metamaterial color filters and Si photodiodes. The metamaterial color filters consisted of guided-mode resonant metal gratings with subwavelength two-dimensional periodic structures. Transmittance characteristics of the color filters were designed to obtain peak wavelengths proportional to grating periods. For each color sensor, a peak wavelength of the spectral sensitivity could be tuned in the range of visible wavelengths by adjusting each grating period. By performing spectrum reconstruction using Tikhonov regularization, the spectrum of an incident light was obtained from the signal of photodiodes. Several monochromatic lights were made incident on the fabricated device and the spectral characteristics of the incident light were reconstructed from the output signals obtained from the respective color sensors. The peak wavelengths of the reconstructed spectra were in good agreement with the center wavelengths of the monochromatic lights.

High‐Efficiency Optical Filters Based on Nanophotonics

“…The incident light spectrum is reconstructed by sequentially reading out the photocurrent generated by each photodiode. Figure 8 shows an example of an SEM micrograph of a wavelength-selective filter composed of the fabricated metamaterial [118]. A two-dimensional periodic structure with a period of 450 nm was fabricated with an accuracy of ±5 nm.…”

Graphene Plasmonics in Sensor Applications: A Review

“…Surface plasmon polaritons (SPPs) and surface plasmon resonance (SPR) are associated with the interactions of electromagnetic waves with the interface between a plasmonic material and a dielectric as a result of the coupling of photons and electrons. Various uses have been proposed for these phenomena in a wide range of applications, including in the fields of biology [ 4 ] and chemistry [ 5 ] and in gas sensing [ 6 ], image sensing [ 7 , 8 ] and optical communication devices [ 9 ]. Conventional plasmonic materials such as Au, Ag and Al can produce SPPs at wavelengths lower than the mid-infrared (IR) region of the spectrum.…”

Fabrication of refractive index sensors using polarization independent metamaterial and their application to chemical concentration measurement and DNA detection

“…Metamaterials are artificial optical materials with a subwavelength structure smaller than incident wavelength; a number of devices were proposed using novel optical phenomena offered by such materials, for example, negative refractive index, cloaking, luminescence enhancement, ultrathin lenses, perfect absorbers, wavelength‐selective filters, etc . Metamaterials are also known to excite localized surface plasmons and to show high sensitivity to changes in ambient refractive index .…”