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Optical Engineering • Open Access

Sensitivity improvement of one-shot Fourier spectroscopic imager for realization of noninvasive blood glucose sensors in smartphones
Author(s): Natsumi Kawashima; Kosuke Nogo; Satsuki Hosono; Akira Nishiyama; Kenji Wada; Ichiro Ishimaru

Paper Abstract

The use of the wide-field-stop and beam-expansion method for sensitivity enhancement of one-shot Fourier spectroscopy is proposed to realize health care sensors installed in smartphones for daily monitoring. When measuring the spectral components of human bodies noninvasively, diffuse reflected light from biological membranes is too weak for detection using conventional hyperspectral cameras. One-shot Fourier spectroscopy is a spatial phase-shift-type interferometer that can determine the one-dimensional spectral characteristics from a single frame. However, this method has low sensitivity, so that only the spectral characteristics of light sources with direct illumination can be obtained, because a single slit is used as a field stop. The sensitivity of the proposed spectroscopic method is improved by using the wide-field-stop and beam-expansion method. The use of a wider field stop slit width increases the detected light intensity; however, this simultaneously narrows the diffraction angle. The narrower collimated objective beam diameter degrades the visibility of interferograms. Therefore, a plane-concave cylindrical lens between the objective plane and the single slit is introduced to expand the beam diameter. The resulting sensitivity improvement achieved when using the wide-field-stop and beam-expansion method allows the spectral characteristics of hemoglobin to be obtained noninvasively from a human palm using a midget lamp.

Paper Details

Date Published: 30 November 2016
PDF: 4 pages
Opt. Eng. 55(11) 110506 doi: 10.1117/1.OE.55.11.110506
Published in: Optical Engineering Volume 55, Issue 11
Show Author Affiliations
Natsumi Kawashima, Kagawa Univ. (Japan)
Kosuke Nogo, Kagawa Univ. (Japan)
Satsuki Hosono, Kagawa Univ. (Japan)
Akira Nishiyama, Kagawa Univ. (Japan)
Kenji Wada, Kagawa Univ. (Japan)
Ichiro Ishimaru, Kagawa Univ. (Japan)

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