Metamaterial based wideband infrared absorbers

Üstün, Kadir
In this thesis, design and simulation of wideband metamaterial absorbers are investigated in the long wave infrared (LWIR) and the mid-wave infrared (MWIR) bands of the electromagnetic spectrum. Use of LWIR and MWIR bands in absorber design is especially important for critical applications including the design of thermal cameras and thermal emitters. Integration of metamaterial topologies into the absorber structures provides flexibilities in design to enhance the operation efficiency of these devices by increasing both absorption levels and operation bandwidths. In this study, we have used different design approaches resulting in various thin metamaterial absorbers that can be fabricated by simple and low-cost optical lithography and yet display outstanding performances. One of the designs consists of two identical and parallel meta-surfaces embedded in a dielectric layer and a ground metal layer. This absorber achieves above 90 percent absorption almost over the whole LWIR region. Another absorber having the basic metal-dielectric-metal topology is based on broadening the absorption window by sculpturing a dispersive and lossy dielectric, silicon nitride. This absorber has covered almost complete LWIR region with at least 90 percent absorption level. Absorbers in the third group consist of a ground metal, a low-loss dielectric layer and a meta-surface, which is deliberately chosen to be a thin lossy metal layer to enhance absorption. These absorber structures are demonstrated to be very successful in the LWIR and MWIR bands. Especially in and around the MWIR band, nearly perfect absorption (at least 98.5 percent) is achieved over an almost octave bandwidth.


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Arslan, Yetkin; Beşikci, Cengiz; Department of Electrical and Electronics Engineering (2014)
This thesis work covers the development of three different state of the art infrared sensor technologies: quantum well infrared photodetectors (QWIPs), HgCdTe sensors and extended InGaAs photodetectors. QWIP is the leading member of the quantum structure infrared photodetector family providing excellent uniformity and stability with field proven performance. The utilization of the InP/In0.48Ga0.52As multi-quantum well structure (instead of the standard AlGaAs/GaAs material system) for the implementation of ...
Development and characterization of low-cost uncooled infrared sensors for commercial applications
Tankut, Firat; Akın, Tayfun; Eminoğlu, Selim; Department of Electrical and Electronics Engineering (2013)
This thesis reports the study on the development and characterization of low-cost uncooled microbolometer type infrared detectors, which are fabricated using standard CMOS and MEMS processes. Characterization of the detectors is the first step of developing infrared sensors with better performance. The characterized pixel has a 70 μm pitch and includes 4 serially connected diodes as the detector circuit. Thermal conductance (Gth), temperature sensitivity (TC) and, optical absorption are measured in scope of...
Diffraction-Grating-Coupled High Quantum Efficiency InP/InGaAs Quantum Well Infrared Photodetector Focal Plane Array
Arslan, Yetkin; Colakoglu, Tahir; Beşikci, Cengiz (2013-02-01)
Quantum well infrared photodetector (QWIP) is still the sole field proven low-cost long-wavelength infrared photon sensor. We report an impressively high quantum efficiency of 31% in the pixels of a large format (640 x 512) grating-coupled InP/In0.48Ga0.52As QWIP focal plane array (FPA). The InP/InGaAs QWIP FPA with a cut-off wavelength of similar to 9 mu m provided desirable characteristics at a temperature as high as 78 K. The noise-equivalent temperature difference of the FPA with f/2 optics is similar t...
High performance near/short wavelength infrared megapixel InGaAs focal plane array fabrication development and new design proposals
Karaca, Utku; Kocaman, Serdar; Department of Electrical and Electronics Engineering (2018)
In0.53Ga0.47As is the most appropriate material system for Short Wavelength Infrared (SWIR) detection at ~1.7 μm cutoff wavelength with its relatively lower cost and high performance. Ultra-low dark current (~ nA/cm2) has been recently demonstrated in InGaAs photodetectors with planar type process by eliminating surface leakage current. Here, a fabrication procedure for planar InGaAs photodetectors with unique pixel isolation methods has been developed and ~10 nA/cm2 dark current density levels were obtaine...
The First Fabricated Dual-Band Uncooled Infrared Microbolometer Detector with a Tunable Micro-Mirror Structure
Keskin, Selcuk; Akın, Tayfun (2012-04-27)
This paper presents the first fabricated dual-band uncooled resistive infrared thermal microbolometer implemented with a resistive microbolometer and a tunable micro-mirror structure. Tunable reflective micro-mirrors are suspended underneath the suspended resistive microbolometers having a 35 mu m pixel pitch, and they are switched between two positions by the application of an electrostatic force for obtaining different responses in two wavelength infrared atmospheric windows, namely the 3-5 and 8-14 mu m,...
Citation Formats
K. Üstün, “Metamaterial based wideband infrared absorbers,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.