Optomechanical uncooled infrared imaging system: design, microfabrication, and performance

Abstract

This paper presents the design, fabrication and performance of an uncooled micro-optomechanical infrared (IR) imaging system consisting of a focal-plane array (FPA) containing bi-material cantilever pixels made of silicon nitride (SiNx) and gold (Au), which serve as infrared absorbers and thermomechanical transducers. Based on wave optics, a visible optical readout system is designed to simultaneously measure the deflections of all the cantilever beams in the FPA and project the visible deflection map onto a visible charge-coupled device (CCD) imager. The IR imaging results suggest that the detection resolution of current design is 3-5 K, whereas noise analysis indicates the current resolution to be around 1 K. The noise analysis also shows that the theoretical noise-equivalent temperature difference (NETD) of the system can be below 3 mK.

Design and analysis of the film assembly of thermo-optic infrared focal plane arrays

“…In recent years, infrared focal plane arrays (FPA) with optical readout, employing various structures (e.g., reflector and grating) supported by cantilever, have been extensively studied by many researchers (Perazzo et al 1999;Ishizuya et al 2001;Zhao et al 2002;Torun and Urey 2006;Huang et al 2006;Dong et al 2007). In such types of the FPA based on bimaterial effect, infrared detection is realized by the deflection, deformation or displacement of the sensing structures which modulate the optical phase difference and the resultant intensity of readout light.…”

“…Infrared detection is of great importance to a variety of applications in civilian fields and especially in military fields, such as remote sensing, environment monitoring and night vision (Zhang and Yang 2001;Zhao et al 2002;Torun and Urey 2006). In recent years, infrared focal plane arrays (FPA) with optical readout, employing various structures (e.g., reflector and grating) supported by cantilever, have been extensively studied by many researchers (Perazzo et al 1999;Ishizuya et al 2001;Zhao et al 2002;Torun and Urey 2006;Huang et al 2006;Dong et al 2007).…”

Enhancing the Responsivity of Uncooled Infrared Detectors Using Plasmonics for High-Performance Infrared Spectroscopy

“…For example, bimetallic microcantilevers with absorptive coatings have been exploited as ultrasensitive thermal sensors for uncooled IR detection and imaging [5,9,10,11]. However, these microcantilever structure-based IR detectors are very susceptible to intrinsic mechanical stresses, external vibrations, and ambient temperature fluctuations.…”

Thermomechanical behavior and microstructural evolution of SiNx/Al bimaterial microcantilevers

“…Subsequently, the deformation can be readily determined by using piezoresistive, optical or capacitive methods [11][12][13][14][15][16].…”