Large-aperture MOEMS Fabry-Perot interferometer for miniaturized spectral imagers

Anna Rissanen, Andreas Langner, Kai Viherkanto, Rami Mannila

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    8 Citations (Scopus)

    Abstract

    VTT’s optical MEMS Fabry-Perot interferometers (FPIs) are tunable optical filters, which enable miniaturization of spectral imagers into small, mass producible hand-held sensors with versatile optical measurement capabilities. FPI technology has also created a basis for various hyperspectral imaging instruments, ranging from nanosatellites, environmental sensing and precision agriculture with UAVs to instruments for skin cancer detection. Until now, these application demonstrations have been mostly realized with piezo-actuated FPIs fabricated by non-monolithical assembly method, suitable for achieving very large optical apertures and with capacity to small-to-medium volumes; however large-volume production of MEMS manufacturing supports the potential for emerging spectral imaging applications also in large-volume applications, such as in consumer/mobile products. Previously reported optical apertures of MEMS FPIs in the visible range have been up to 2 mm in size; this paper presents the design, successful fabrication and characterization of MEMS FPIs for central wavelengths of λ = 500 nm and λ = 650 nm with optical apertures up to 4 mm in diameter. The mirror membranes of the FPI structures consist of ALD (atomic layer deposited) TiO2-Al2O3 λ/4- thin film Bragg reflectors, with the air gap formed by sacrificial polymer etching in O2 plasma. The entire fabrication process is conducted below 150 °C, which makes it possible to monolithically integrate the filter structures on other ICdevices such as detectors. The realized MEMS devices are aimed for nanosatellite space application as breadboard hyperspectral imager demonstrators.
    Original languageEnglish
    Title of host publicationMOEMS and Miniaturized Systems XIV
    PublisherInternational Society for Optics and Photonics SPIE
    DOIs
    Publication statusPublished - 27 Feb 2015
    MoE publication typeA4 Article in a conference publication
    EventMOEMS and Miniaturized Systems XIV - San Francisco, United States
    Duration: 9 Feb 201512 Feb 2015

    Publication series

    SeriesProceedings of SPIE
    Volume9375
    ISSN0277-786X

    Conference

    ConferenceMOEMS and Miniaturized Systems XIV
    CountryUnited States
    CitySan Francisco
    Period9/02/1512/02/15

    Keywords

    • hyperspectral sensors
    • Fabry-Perot Interferometer
    • MEMS
    • imaging spectrometer

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