Sensitivity improvement of one-shot Fourier spectroscopic imager for realization of noninvasive blood glucose sensors in smartphones

Kawashima, Natsumi; Nogo, Kosuke; Hosono, Satsuki; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

doi:10.1117/1.oe.55.11.110506

Cited by 5 publications

(1 citation statement)

References 16 publications

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“…The spread of novel coronavirus infections in recent years has led to an increased demand for inexpensively available, uncooled mid-infrared microbolometer array sensors. In addition, mid-infrared spectroscopy is being adapted to everyday life spaces, such as in the example of non-invasive blood glucose level sensors for health care [1] . Against this background, we developed a palm-sized mid-infrared imaging-type two-dimensional Fourier spectrometer [2] .…”

Section: Introductionmentioning

confidence: 99%

Mid-infrared passive spectroscopic imaging with an uncooled microbolometer array sensor

Morimoto

Tahara²,

Yamashita³

et al. 2022

Electro-Optical and Infrared Systems: Technology and Applications XIX

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We aim to measure the glucose concentration in the body through passive mid-infrared spectroscopy using a palm-sized imaging two-dimensional Fourier spectrometer. Radiation in the mid-infrared region (at a wavelength of approximately 10 µm) is emitted from the object surface, with the intensity of the radiated light corresponding to the object temperature. Passive spectroscopy acquires component information from the spectral intensity of the radiated light emitted from the object without a light source. Intrinsic vibrations of molecules in the object itself are detected, and the spectral characteristics are thus the emission spectrum of intrinsic vibration peaks. In contrast, conventional active spectroscopy irradiates the measurement target with light and acquires spectral characteristics from the reflected light. Molecular vibrations excited by the light source are measured, and the spectral characteristics are thus absorption spectra of the energy absorbed at the eigenfrequency of the molecule. The wavelengths that are confirmed as absorption wavelengths in active spectroscopy are confirmed as emission wavelengths in passive spectroscopy. Active spectroscopy and passive spectroscopy thus have a negative–positive relationship. The imaging-type two-dimensional Fourier spectrometer (7 to 14 µm) used in past measurement has transmission optics. Using three Ge lenses for the front lens, objective lens, and imaging lens, we constructed reflective optics using reflective mirrors for the objective and imaging lenses. The reflective mirror guarantees flatness and high spectral reflectance over a wide bandwidth (3 to 20 µm), and the measurement bandwidth is thus extended.

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Section: Introductionmentioning

confidence: 99%