Matrix Structure of Metamaterial Absorbers for Multispectral Terahertz Imaging

Abstract

Abstract-A multispectral 24 × 24 bolometric matrix structure of terahertz (THz) absorbers operating at 0.3-0.4 THz was proposed and experimentally investigated. Each pixel of the structure was implemented as a fragment of an ultra-thin metamaterial absorber. The matrix structure consisted of four types of pixels with nearly perfect absorptivity. Three pixels were at 0.30, 0.33, 0.36 THz respectively with identically oriented polarization sensitivity, and the fourth pixel was at 0.33 THz oriented with polarization sensitivity orthogonal to foregoing ones. The backside of the structure included a high-performance infrared emissive layer. Resonant absorption of THz radiation induced the structure heating and increasing IR emission from the emissive layer, which was henceforth detected by the IR camera. The terahertz imaging system, capable to operate in real time, with spectral and polarization discrimination was demonstrated. The experimental results showed good spectral and polarization resolution together with acceptable spatial resolution.

A Family of Ultra-Thin, Polarization-Insensitive, Multi-Band, Highly Absorbing Metamaterial Structures

“…Since modern practical applications require more sophisticated characteristics, such as larger bandwidths or multiple bands of operation as well as wide-angle and polarization-independent responses, a significant research has been triggered -and yet to be expected -for the improvement of these absorbers' overall behavior [10][11][12][13][14][15][16][17][18][19]. Apparently, this is a critical issue for various electromagnetic interference/electromagnetic compatibility (EMI/EMC) problems, like radar-cross section minimization from airplanes, steamboats and other vehicles, EMI protection owing to mobile phones and local area networks, light-trapping structures for photovoltaic systems or terahertz imaging devices [20][21][22][23][24][25].…”

Terahertz Sensing Application by Using Fractal Geometries of Split-Ring Resonators

“…Since numerical and experimental studies of the first splitring-resonator-based MTM structure in the microwave region [1][2][3][4], this kind of structure has been used in many applications such as sensing [1,3,5], absorber [6][7][8], superlensing [9][10][11], and so on. With respect to sensing, MTMs have been proven to be good candidates in the THz regime for highly sensitive chemical or biological detection since the unit cell dimensions are typically sub-wavelength and frequency response can be tuned according to their shape and geometrical dimensions [12][13][14].…”

DESIGN AND 3-D PARTICLE-IN-CELL SIMULATION OF A 140 GHz SPATIAL-HARMONIC MAGNETRON

“…Recent years have seen increased interest in the Terahertz (THz) region of the electromagnetic spectrum because of a number of potential applications in industrial quality control, remote sensing, stand-off detection of chemical and biological agents, medical imaging, ultra high speed data communications, all weather visibility systems, astrophysics, and spectroscopy [1][2][3][4]. Although various components have been developed for THz applications [5][6][7][8][9][10][11][12][13][14][15][16][17][18], high power, low cost, and compact THz sources are not readily available [19].…”