Elimination of Unwanted Modes in Wavelength-Selective Uncooled Infrared Sensors with Plasmonic Metamaterial Absorbers using a Subtraction Operation

Abstract

Wavelength- or polarization-selective uncooled infrared (IR) sensors have various applications, such as in fire detection, gas analysis, hazardous material recognition, biological analysis, and polarimetric imaging. The unwanted modes originating due to the absorption by the materials used in these sensors, other than plasmonic metamaterial absorbers (PMAs), cause serious issues by degenerating the wavelength or polarization selectivity. In this study, we demonstrate a method for eliminating these unwanted modes in wavelength- or polarization-selective uncooled IR sensors with various PMAs, using a subtraction operation and a reference pixel. The aforementioned sensors and the reference pixels were fabricated using a complementary metal oxide semiconductor and micromachining techniques. We fabricated the reference pixel with the same structure as the PMA sensors, except a flat mirror was formed on the absorber surface instead of PMAs. The spectral responsivity measurements demonstrated that single-mode detection can be achieved through the subtraction operation with the reference pixel. The method demonstrated in this study can be applied to any type of uncooled IR sensors to create high-performance wavelength- or polarization-selective absorbers capable of multispectral or polarimetric detection.

Multi-spectral uncooled infrared sensors fabricated using encapsulated metal-insulator-metal plasmonic metamaterial absorbers

“…The thermopiles were fabricated on a Si substrate using a standard CMOS process, as previously reported. 18 A series of p-and n-type poly-Si regions formed thermocouples, and the ion implantation dose controlled their resistivity. An Al layer was deposited under the absorber as a bottom reflector, and holes were formed via reactive ion etching.…”

Black phosphorous/graphene van der Waals heterostructure-based plasmonic metasurfaces for advanced infrared photodetectors

“…24,25 Therefore, BP is still gaining importance. Moreover, advanced functional IR photodetectors with wavelength [26][27][28][29] or polarization selectivity 30 are expected to expand the application field of BP-based IR photodetectors. In the present study, we theoretically investigate BP-based IR photodetectors with advanced functions such as wavelength selectivity.…”

Current-Mode Self-Amplified CMOS Sensor Intended for 2D Temperature Microgradients Measurement and Imaging

“…Regarding the uncooled thermal image sensors, some papers present contributions considering area reduction, enhancement of responsivity and sensitivity, signal readout process, image processing, power consumption and noise equivalent temperature difference (NETD) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. It is desirable to have these sensors integrated into standard CMOS technology to reduce the costs and to facilitate embedding the interface and the readout electronic circuitry [ 1 , 2 , 4 , 5 , 7 , 10 , 11 , 12 , 17 , 18 ]. Among those sensors having some degree of integration, none can be fabricated without changes to the standard CMOS process: breaking some design rules, adjusting process steps/sequence or by performing post-processing steps [ 1 , 2 , 4 , 5 , 7 , 10 , 11 , 12 , 17 , 18 ].…”

“…It is desirable to have these sensors integrated into standard CMOS technology to reduce the costs and to facilitate embedding the interface and the readout electronic circuitry [ 1 , 2 , 4 , 5 , 7 , 10 , 11 , 12 , 17 , 18 ]. Among those sensors having some degree of integration, none can be fabricated without changes to the standard CMOS process: breaking some design rules, adjusting process steps/sequence or by performing post-processing steps [ 1 , 2 , 4 , 5 , 7 , 10 , 11 , 12 , 17 , 18 ]. Besides the uncooled thermal image sensors, there have been developments in the cooled infrared sensors, even though they are more expensive and usually not integrated with CMOS signal processing circuits [ 21 , 22 , 23 , 24 , 25 , 26 ].…”