Active Hyperspectral Sensor Based on MEMS Fabry-Pérot Interferometer

Kääriäinen, Teemu; Jaanson, Priit; Vaigu, Aigar; Mannila, Rami; Manninen, Albert

doi:10.3390/s19092192

Cited by 14 publications

(9 citation statements)

References 24 publications

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“…Deposition of thin film of TiO 2 on glass substrate using electron beam evaporation causes tensile residual stress in the order of 170 MPa [ 38 ]. While deposition of thin film of SiO 2 on a thin film of TiO 2 causes a compression stress in the same order to form [ 39 , 40 ]. Deposition of silver on the other hand causes a tensile stress in the order of 18 Pa which gives a radius of curvature in the range of thousands of kilometers according to Stoney’s equation [ 38 ].…”

Section: Device Designmentioning

confidence: 99%

“…Fabry-Pérot filters are known to be dependent on the angle of incidence; therefore, for real life imaging applications will dictate the filter to be inserted in an optical system that allow rays collection, and collimate them on the filter. Such systems have been presented earlier in the literature [ 40 ]. Some systems allow for a field of view of 30 degrees [ 41 ].…”

Section: Device Designmentioning

confidence: 99%

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Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging

et al. 2021

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Hyperspectral imaging has a wide range of uses, from medical diagnostics to crop monitoring; however, conventional hyperspectral imaging systems are relatively slow, bulky, and rather costly. In this paper, we present an inexpensive, compact tunable optical filter for hyperspectral applications. The filter is based on a Fabry-Pérot interferometer utilizing hybrid metallic-dielectric mirrors and actuated using a MEMS electrostatic actuator. The optical filter is designed using the transfer matrix method; then, the results were verified by an electromagnetic wave simulator. The actuator is based on a ring-shaped parallel plate capacitor and is designed using COMSOL Multiphysics. An actuation displacement of 170 nm was used, which is the required distance to tune the filter over the whole visible range (400–700 nm). There are two designs proposed for the optical filter: the first was optimized to provide maximum transmission and the other is optimized to have minimum full-width-half-maximum (FWHM) value. The first design has a maximum transmission percentage of 94.45% and a minimum transmission of 86.34%; while the minimum FWHM design had an average FWHM value of 7.267 nm. The results showed improvements over the current commercial filters both in transmission and in bandwidth.

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Section: Device Designmentioning

confidence: 99%

Section: Device Designmentioning

confidence: 99%

Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging

et al. 2021

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“…10 There are numerous published reports on MEMS-based narrowband FPIs in the short-wavelength infrared and midwavelength infrared regions. 6,8,[11][12][13][14][15][16][17] However, very limited reports are available on MEMS-based narrowband FPIs in the long-wavelength infrared (LWIR) region due to challenges involved in the fabrication processes and the lack of suitable optomechanical materials in the LWIR band. Some of the published studies on LWIR FPIs include surface micromachined narrowband filters using Si-Air-Si based DBRs by VTT, 18,19 which gave an FWHM of 140 nm.…”

Section: Introductionmentioning

confidence: 99%

Large-area narrowband Fabry–Pérot interferometers for long-wavelength infrared spectral sensing

Gill

Zawierta

Tripathi

et al. 2022

J. Optical Microsystems

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This paper presents a proof-of-concept for microelectromechanical system (MEMS)based fixed cavity Fabry-Pérot interferometers (FPIs) operating in the long-wavelength infrared (LWIR, 8 to 12 μm) region. This work reports for the first time on the use of low-index BaF 2 thin films in combination with Ge high-index thin films for such applications. Extremely flat and stress-free ∼3-μm-thick free-standing distributed Bragg reflectors (DBRs) are also presented in this article, which were realized using thick lift-off of a trilayer structure fabricated using Ge and BaF 2 optical layers. A peak-to-peak flatness was achieved for free-standing surface micromachined structures within the range of 10 to 20 nm across large spatial dimensions of several hundred micrometers. Finally, the optical characteristics of narrowband LWIR fixed cavity FPIs are also presented with a view toward the future realization of tunable wavelength MEMS-based spectrometers for spectral sensing. The measured optical characteristics of released FPIs agree with the modeled optical response after taking into consideration the fabrication-induced imperfections in the free-standing top DBR such as an average tilt of 15 nm and surface roughness of 25 nm. The fabricated FPIs are shown to have a linewidth of ∼110 nm and a suitable peak transmittance value of ∼50%, which meets the requirements for their utilization in tunable MEMS-based LWIR spectroscopic sensing and imaging applications requiring spectral discrimination with narrow linewidth.

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“…Active hyperspectral sensor (AHS) [1][2][3][4][5] is capable of remote spectral reflectance measurement using a supercontinuum (SC) light as an active source. Due to differences in spectral absorption by different materials, the remotely measured spectra could be used to identify materials such as fabrics, skin and metals from vegetation.…”

Section: Introductionmentioning

confidence: 99%

Active hyperspectral sensing for border control

Kääriäinen

Mekhrengin

Dönsberg

2021

Electro-Optical and Infrared Systems: Technology and Applications XVIII and Electro-Optical Remote Sensing XV

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There is a need for sensor technologies capable of identifying illegal border crossings through foliage. In this work, we study the use of a novel active hyperspectral sensor for remote identification of persons and vehicles through foliage. The AHS sensor is based on a continuously tunable near-infrared supercontinuum light source and a microelectromechanical Fabry-Pérot interferometer for transmission band selection. Real-time spectral detection algorithms are used to identify the targets based on the spectral content of the back-scattered light. Preliminary results are presented from both in-lab and outdoors.

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Active Hyperspectral Sensor Based on MEMS Fabry-Pérot Interferometer

Cited by 14 publications

References 24 publications

Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging

Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging

Large-area narrowband Fabry–Pérot interferometers for long-wavelength infrared spectral sensing

Active hyperspectral sensing for border control

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