Novel uncooled infrared detectors

Rogalski, Antoni

doi:10.2478/s11772-010-0059-y

Cited by 5 publications

(2 citation statements)

References 61 publications

(114 reference statements)

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“…In contrast, thermal detectors transduce IR radiation by measuring a temperature-dependent physical property such as electrical resistance in bolometers 7 , electrical polarization in pyroelectric detectors 8 , electrical voltage in thermopiles 9 , and displacement in thermomechanical detectors 10 . They do not require active cooling, and can be small and power efficient 11 . However, they lag behind photon detectors in terms of sensitivity and response time.…”

Section: Introductionmentioning

confidence: 99%

Shape memory polymer resonators as highly sensitive uncooled infrared detectors

et al. 2019

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Uncooled infrared detectors have enabled the rapid growth of thermal imaging applications. These detectors are predominantly bolometers, reading out a pixel’s temperature change due to infrared radiation as a resistance change. Another uncooled sensing method is to transduce the infrared radiation into the frequency shift of a mechanical resonator. We present here highly sensitive resonant infrared sensors, based on thermo-responsive shape memory polymers. By exploiting the phase-change polymer as transduction mechanism, our approach provides 2 orders of magnitude improvement of the temperature coefficient of frequency. Noise equivalent temperature difference of 22 mK in vacuum and 112 mK in air are obtained using f/2 optics. The noise equivalent temperature difference is further improved to 6 mK in vacuum by using high-Q silicon nitride membranes as substrates for the shape memory polymers. This high performance in air eliminates the need for vacuum packaging, paving a path towards flexible non-hermetically sealed infrared sensors.

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Section: Introductionmentioning

confidence: 99%

Shape memory polymer resonators as highly sensitive uncooled infrared detectors

et al. 2019

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“…The NEdT has been reduced to a value lower than 50 mK in recent studies. [22][23][24][25] In contrast, the torsional resonator can detect the temperature using the resonant frequency shift of a mechanical vibration. Thus, the effect of thermal noise is relatively small.…”

Section: Introductionmentioning

confidence: 99%

Micromechanical IR thermal detector using torsional oscillation: Improvement of resonator profile for high sensitivity

Jeong

Kumagai

Yamashita

et al. 2015

Jpn. J. Appl. Phys.

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An infrared (IR) thermal detector, which used the torsional oscillation of a micromechanical resonator, was developed to achieve a high sensitivity. The detector has a bimaterial structure consisting of a tense Si film (oscillating body) and a metal film (IR absorber). Owing to the difference in thermal expansion between the two materials, the resonator is bent by light incidence. Because the axis of torsion is bent from the initial flat state, the spring for torsional oscillation hardens and resonant frequency shifts. To enhance bending, an Al film with a large coefficient of thermal expansion was used. In addition, the tension in the polycrystalline Si film was enhanced by metal-induced lateral crystallization using biomineralized Ni nanoparticles. The fabricated detector was flat under initial conditions and showed a bending response to the light incidence and heating. The present IR detector achieved a thermal coefficient of frequency of 1000 ppm/K, which was one order larger than that of the conventional micromechanical IR sensors.

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