Uncooled microbolometer detector: recent developments at Ulis

Tissot, Jean-Luc; Trouilleau, C.; Fièque, B.; Crastes, A.; Legras, O.

doi:10.1117/12.621884

Cited by 8 publications

(6 citation statements)

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“…Without specification about the type of sensor used, we are forced to test the two possibilities. Fortunately, the spectral response has been found in the literature (VOx sensor in reference [5] and of a-Si one in reference [6]). For each of them, spectral response is characterized by absorptivity with the aid of an IR spectrometer equipped with an integration sphere or by detectivity (FTIR spectrometer).…”

Section: Apparent Emissivity Calculationmentioning

confidence: 99%

A self - method for solving the problem of LWIR spectral band of camera for quantitative thermography

Riou¹,

Logerais²,

Delaleux³

et al. 2014

Proceedings of the 2014 International Conference on Quantitative InfraRed Thermography

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In a previous work, we succeeded in connecting normal LWIR apparent emissivity to the spectral one of an aluminium nitride ceramic plate. We showed a good agreement with the assumption of spectral bandwidth of the used IR system. Our aim in this paper is to justify the considered spectral band [7.5µm, 12µm]. Hence we have developed an analyzer of IR system. The analyzer proceeds by comparing thermosignals with integrated blackbody radiance and adapts spectral bandwidth in order to minimize the dispersion from linearity of the characteristic thermosignals / integrated radiance over a temperature range of the IR system. The capacities of the analyzer are tested for 6 commercial cameras. Each of these systems exhibits a similar formatting process implemented during the thermogram recording. The effective spectral bandwidth exhibits plausible values. It varies significantly from one model to the other and the residual non-linearity is connected to the NETD of the IR system. Applied to the same system which served to characterize the apparent emissivity, the analyzer permits to quantify the effective spectral band. We obtain an excellent agreement between the classical model of apparent emissivity and measurement, both in terms of accuracy and in terms of temperature dependence. The absolute error is 0.005 for emissivity and the temperature coefficient is less than 6 10-5 °C-1 within the temperature range [40°C, 130°C].

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Section: Apparent Emissivity Calculationmentioning

confidence: 99%

A self - method for solving the problem of LWIR spectral band of camera for quantitative thermography

Riou¹,

Logerais²,

Delaleux³

et al. 2014

Proceedings of the 2014 International Conference on Quantitative InfraRed Thermography

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“…As a consequence, reductions in pixel size increase the cutoff frequency, but they also reduce the sensitivity to IR irradiation. This tradeoff limits the frequency response of traditional microbolometers to about 30–60 Hz 1 – 3 . Umbrella-type microbolometers 4 having a double-layer structure attempt to overcome this limitation by using a space-filling metal/dielectric layer to maximize the absorbed IR energy 5 .…”

Section: Introductionmentioning

confidence: 99%

Nanoantenna-based ultrafast thermoelectric long-wave infrared detectors

Szakmany

Bernstein

Kinzel

et al. 2020

Sci Rep

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We investigate the generation of electrical signals by suspended thermoelectrically coupled nanoantennas (TECNAs) above a quasi-spherical reflector cavity in response to rapidly changing long-wave infrared radiation. These sensors use a resonant nanoantenna to couple the IR energy to a nanoscale thermocouple. They are positioned over a cavity, etched into the Si substrate, that provides thermal isolation and is designed as an optical element to focus the IR radiation to the antenna. We study the frequency-dependent response of such TECNAs to amplitude-modulated 10.6 μm IR signals. We experimentally demonstrate response times on the order of 3 μs, and a signal bandwidth of about 300 kHz. The observed electrical response is in excellent correlation with finite element method simulations based on the thermal properties of nanostructures. Both experiments and simulations show a key trade-off between sensitivity and response time for such structures and provide solutions for specific target applications.

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“…Maximizing absorption in a system with low thermal mass is crucial, for example, in microbolometers and other thermal detectors. In a traditional microbolometer, one attempts to reduce mass in order to achieve a lower thermal time constant (in other words, faster response) [3,17,19]. For high performance radiationlimited thermal detectors, the concept is a bit more subtle.…”

Section: Introductionmentioning

confidence: 99%

Enhanced absorption per unit mass for infrared arrays using subwavelength metal–dielectric structures

Das¹,

Talghader²

2020

J. Opt. Soc. Am. B

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The absorption-to-mass ratio of the infrared arrays is enhanced to ~1.33 ̶ 7.33 times larger than the previously reported structures by incorporating two design characteristics: first, the coupling of evanescent fields in the air gaps around pixels to create effectively larger pixel sizes, and, second, the use of guided mode resonance (GMR) within the subwavelength metaldielectric gratings. The bilayer Ti-Si3N4 gratings achieve broadband long-wave infrared (LWIR,  ~ 8 ̶ 12 m) absorption by the combined effects of free carrier absorption by the thin Ti films and vibrational phonon absorption by the thick Si3N4 films. In the presence of GMR, this broadband absorption can be enormously enhanced even with low fill factor subwavelength grating cells. Further, the spacing and design of the cells can be modified to form a pixel array structure that couples the light falling in the air gaps via evanescent field coupling. Calculations are performed using the finite difference time domain (FDTD) technique. Excellent broadband absorption is observed for the optimized arrays, yielding maximum absorption of 90% across the LWIR and an average absorption-per-unit-mass (absorption/mass) per pixel of 3.45×10 13 kg -1 .

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Uncooled microbolometer detector: recent developments at Ulis

Cited by 8 publications

References 0 publications

A self - method for solving the problem of LWIR spectral band of camera for quantitative thermography

A self - method for solving the problem of LWIR spectral band of camera for quantitative thermography

Nanoantenna-based ultrafast thermoelectric long-wave infrared detectors

Enhanced absorption per unit mass for infrared arrays using subwavelength metal–dielectric structures

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