Optical readout method for microcantilever array sensing and its sensitivity analysis

Miao, Zhengyu; Zhang, Qingchuan; Wu, Xiaoping; Chen, Dapeng

doi:10.1364/ol.32.000594

Cited by 24 publications

(17 citation statements)

References 6 publications

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“…We also calculated the NETD using the aforesaid simulation results. ΔI/ΔT s was expressed as ΔI/ΔT s = (ΔT c /ΔT s ) × (Δθ/ΔT c ) × (ΔI/Δθ), where ΔI/Δθ is the optical detecting sensitivity of the imaging system [10]. The average ΔI/Δθ value was experimentally estimated to be 3180 gray levels/ • .…”

Section: Experiments and Calculationmentioning

confidence: 99%

Uncooled Infrared Imaging Using a Substrate-Free Focal-Plane Array

Cheng

Zhang

et al. 2008

IEEE Electron Device Lett.

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A substrate-free 160 × 160 focal-plane array (FPA) with a 60-µm × 60-µm pitch has been developed and used for an optical readout uncooled infrared (IR) detector. The supporting frame of the FPA is a temperature-variable one due to its large decreases in both heat capacity and thermal conductance. This thermal characteristic significantly increases the temperature change of the microcantilever, which depends on both the temperature change induced by its absorption of IR radiation and the linear superposition of the temperature prechange induced by other microcantilevers, and therefore improves the performance of the substrate-free FPA. In the proposed IR detector, the fabricated FPA had an average noise equivalent temperature difference (NETD) and a response time of 330 mK and 16 ms, respectively. Its performance increased by about 4.3 times compared with that of the substrate FPA that consists of the same microcantilevers.Index Terms-Focal-plane array (FPA), infrared (IR) detectors, substrate-free, uncooled.

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Section: Experiments and Calculationmentioning

confidence: 99%

Uncooled Infrared Imaging Using a Substrate-Free Focal-Plane Array

Cheng

Zhang

et al. 2008

IEEE Electron Device Lett.

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“…This therefore seriously decreases the optical readout sensitivity. 12 The average ⌬I / ⌬ value was experimentally measured to be 1.82ϫ 10 5 gray levels/ rad, which is far below the theoretical prediction of 8.68ϫ 10 5 gray levels/ rad. Based on the aforesaid analyses, the predictions for both the fabricated FPA and the substrate FPA can thus be calculated to be 43 and 6.6 gray levels/K, respectively.…”

Section: Netdmentioning

confidence: 78%

Performance of an optimized substrate-free focal plane array for optical readout uncooled infrared detector

Cheng

Zhang

Chen

et al. 2009

Journal of Applied Physics

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This note presents an optimized substrate-free focal plane array ͑FPA͒, which is implemented in an optical readout uncooled infrared ͑IR͒ detector. The supporting frame of such FPA is a temperature-variable one due to the large decreases in both the heat capacity and the thermal conductance. This brings a unique thermal characteristic: the supporting frame functions as a "thermal isolation" frame which reduces the thermal conductance and therefore increases the temperature change and also functions as a "thermal diffusion" frame which certainly results in the temperature prechange in the ones not absorbing IR radiation. This characterization could significantly increase the temperature change of microcantilevers and therefore improve the performance of the substrate-free FPA. In the proposed IR detector, the fabricated 160ϫ 160 FPA has an average noise equivalent temperature difference ͑NETD͒ and a response time of 330 mK and 16 ms, respectively. The performance of the IR detector theoretically increases by about 5.5 times compared with the one using a substrate FPA. Here, the geometry of the substrate FPA is just the same as the fabricated FPA, but the supporting frame is assumed to be a temperature-constant one. If the optical readout sensitivity can be increased enough using an enhanced IR absorber, the fabricated FPA thus has the potential to achieve a NETD value of 70 mK.

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“…Thus, in a predetermined element size, the reflector length along the leg direction is required to be as long as possible to minimize y min . If the reflector has an initial bend caused by residual stress, the spectrum will be dispersed and widened, then the optical detecting sensitivity y min will degrade [16]. In fact, this case is inevitable in the FPA fabrication process.…”

Section: Principle Of Optical Readout Systemmentioning

confidence: 99%

“…When t SiN x is reduced to 0.3 mm, the thickness ratio approaches to the optimum and the product S T Â H reaches 1.3 Â 10 À2 deg/K, about 10 times of the current value. It should be noted that the absorptance of IR fluxes depends on the SiN x film thickness by 1Àexp(À4t SiN x pk/l 1 ) [16], where k is the absorption coefficient of SiN x and l 1 the wavelength of IR radiation. In the 8-14 mm spectral range, the absorptance is only about 32% when t SiN x reduces to 0.3 mm (for l 1 $10 mm, k$1 [17]).…”

Section: Article In Pressmentioning

confidence: 99%