Chien-Yuan Han

Noninvasive glucose monitoring in vivo with an optical heterodyne polarimeter

An amplitude-sensitive optical heterodyne polarimeter was set up to monitor noninvasively the aqueous glucose concentration in a rabbits eye. A Zeeman laser in conjunction with a Glan-Thompson analyzer was used to generate an optical heterodyne signal. The amplitude of the heterodyne signal linearly related to the optical rotation angle of the aqueous glucose. The concentration of the aqueous glucose in a rabbits eyeball was measured in vivo. There was a 30-min time delay between observations of aqueous glucose and blood glucose. The detection capability and the reproducibility of the experiment are demonstrated and discussed.

Photoelastic modulated imaging ellipsometry by stroboscopic illumination technique

A novel stroboscopic illumination technique is applied in a photoelastic modulated (PEM) ellipsometry to conquer the slow imaging processing of charge-coupled device camera system and form a fast imaging ellipsometry. The synchronized ultrastable short pulse is used to freeze the intensity variation of the PEM modulated signal. The temporal phase is calibrated with respect to the time reference of PEM. The laser diode is modulated by a programable pulse generator for triggering four short pulses at their specific temporal phase angle. The two-dimensional (2D) ellipsometric parameters can be deduced from those recorded four images. Therefore, the 2D thickness profile of a patterned sample can be measured; a static patterned SiO2 thin film on silicon substrate and the drainage behavior of matching oil on silicon wafer were studied by this imaging ellipsometry.

Determination of optical parameters of a twisted-nematic liquid crystal by phase-sensitive optical heterodyne interferometric ellipsometry

What is believed to be a novel phase-sensitive optical heterodyne interferometric ellipsometer is set up to characterize a twisted-nematic liquid crystal (TN-LC) by the elliptical parameters of the output polarization state. This ellipsometer presents the advantages of both polarized optical heterodyne interferometry and optical photometry, which introduce a polarization modulation that is capable of performing with high-sensitivity on phase detection in real time. The twist angle phi and the untwisted phase retardation gamma of TN-LC are measured precisely. The experimental results verify that a TN-LC can be treated as identical to an elliptical retarder.

Circularly polarized optical heterodyne interferometer for optical activity measurement of a quartz crystal

Phase retardation between two orthogonal circularly polarized light waves that propagate in an optical active medium is proportional to its optical activity. The measurement of optical activity of a quartz depolarizer in terms of the phase difference of two orthogonal circularly polarized waves is proposed. A circularly polarized optical heterodyne interferometer with a Zeeman laser to measure the optical activity of a quartz crystal is demonstrated experimentally. The accuracy of the measurement is discussed. In addition, the effect of elliptical polarization and nonorthogonality of linearly polarized light waves of a Zeeman laser on the optical activity measurement is analyzed.

TN-LC cells as an Elliptical Phase Retarder by heterodyne interferometric ellipsometry

A polarized heterodyne ellipsometer to characterize TN-LC by elliptical parameters of polarization state is proposed. The twist angle and untwisted phase retardation can be measured precisely that TN-LC is verified as an elliptical retarder properly

Photoelastic Modulated Imaging Ellipsometry in Surface Plasmon Resonance Detection

The photoelastic modulated (PEM) imaging ellipsometry is used to measure the immobilization of Protein A on biochip through the micro-channel. Its lateral and temporal resolution of ellipsometric parameters are 4μm and 13sec, respectively.

Detecting E.coli-O157 with fiber optic biosensor

We develop a fiber-optic biosensor system for rapid identification of E.coli-O157 and calculate the kinetics of IgG.

The kinetics of beta-amyloid protein polymerization using surface plasmon resonance biosensor

In this study, A/spl beta//sub 1-42/ aggregation was analyzed, the results show that the association rate constant (k/sub a/) is strongly dependent upon the A/spl beta/ concentration, but the dissociation rate constant (k/sub d/) has no significant change. The A/spl beta//sub 1-42/ protein is capable of higher tendency than A/spl beta//sub 1-40/ to produce self-assembly.

Twisted nematic liquid crystal as an elliptical retarder

A three-intensity technique is applied in polarimetry for measuring the twisted angle and phase retardation of a twisted nematic liquid crystal. The TN-LC is considered as an elliptical retarder, its ellipse angle is studied and measured.