S. Takahashi

Institute for Infocomm Research, Tumasik, Singapore

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Publications (6)4.83 Total impact

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    ABSTRACT: This letter reports the measurement of single living cell’s refractive index �RI� using the optical grating resonant cavity with buffer modulation on a biochip. The cell’s RI is a significant cell biophysical property which has potential in cancer and disease diagnoses. The single cell is trapped optically within the cavity, and the transmission spectra shift due to the change of surrounding buffer, without/with cell, are used to determine the cell’s effective RI and effective thickness. The measurement shows that Madin-Darby canine kidney cell has an effective RI of 1.383±0.001. Moreover, the optical trapping technique eliminates uncertainty and avoids cell damage.
    Applied Physics Letters 12/2007; 91(24):243901. · 3.79 Impact Factor
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    ABSTRACT: This paper reports a single cell refractometer consists of FBG fiber-based resonant cavity by employing buffer modulation method. In this biophotonic chip, single cell is trapped optically in the cavity, and the transmission spectral shifts due to the change of surrounding buffer, without and with cell, are used to determine the cell's refractive index (Rl) and size. The measurement shows that MDCK cell has an effective Rl of 1.383 at a precision of 0.1%. Moreover, the measurement method with optical trapping eliminates uncertain factors and prevents cell damage. The chip is promising for label-free cell measurement and further cell analysis.
    Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS 2007. International; 07/2007
  • J Hao, C.Y. Liaw, S Takahashi, Z Cai, T.H. Cheng, C Lu
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    ABSTRACT: A wavelength reference was constructed by illuminating an athermal silica-based Mach-Zehnder interferometer filter with a broadband light source. The wavelength-voltage response of a Fabry-Perot tunable filter can be calibrated by using the constructed wavelength reference.
    Optical Fiber Communication and the National Fiber Optic Engineers Conference, 2007. OFC/NFOEC 2007. Conference on; 04/2007
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    ABSTRACT: A pair of FBG embedded symmetrically in an elastic bending beam, resulting the two peak wavelengths moving apart with the downwards-applied lateral force and moving together in the same direction when surrounding temperature changes, both linearly. Proper calibration makes such arc-shaped FBG sensor capable of simultaneous measurement of both temperature and lateral force. A module with such structure is studied both theoretically and experimentally.
    International Symposium on Circuits and Systems (ISCAS 2007), 27-20 May 2007, New Orleans, Louisiana, USA; 01/2007
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    ABSTRACT: A report is presented on the effect of bending on the sidelobe power of the reflection spectrum in fibre Bragg grating (FBG) lateral force sensors. Under four-point bending, force detection improves drastically up to 250 N.
    Electronics Letters 12/2005; · 1.04 Impact Factor
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    ABSTRACT: Embedded fiber Bragg gratings (FBGs) have been fabricated for use as pressure sensors to measure forces applied in the direction perpendicular to the fiber axis. The 1 cm length acrylate-coated FBGs were embedded into fiber-reinforced composites in two orientations in separate samples to test the properties of pressure sensor in each case. In samples where the FBG is embedded in parallel to the carbon fiber, the reflected spectrum remains a single wavelength peak as expected from an FBG. However, for samples where the FBG is placed at 90deg to the carbon fiber, peak split was observed. Scanning electron microscopy (SEM) of the embedded acrylate-coated fiber shows that the FBG embedded parallel to the carbon fiber is wrapped completely while the FBG embedded at 90deg to the carbon fiber is difficult to be wrapped well, suggesting the existence of longitudinal inhomogeneity
    Communications Systems, 2004. ICCS 2004. The Ninth International Conference on; 10/2004