Browsing by Author "Jian, ZC"

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A method for measuring the complex refractive index of a turbid medium
(2005)
Jian, ZC
;
Lin, JY
;
Hsieh, PJ
;
Chen, HW
;
Su, DC
Based on the heterodyne interferometry and Fresnel equations, an alternative method for measuring the complex refractive index of a turbid medium. A light beam is incident on the boundary between a right-angle prism and a turbid medium. The phase difference between s- and p- polarizations of the reflected light occurs. The phase difference depends on then incident angle and the complex refractive index of a turbid medium-, their relation can be derived from Fresnel equations. The phase difference can be measured accurately with the heterodyne interferometry. Because there are two unknown parameters to be estimated, at least the phase differences under two different conditions should be measured. Then, these measured data are substituted into the derived relation, and a set simultaneous equation is obtained. If the simultaneous equation is solved. the complex refractive index can be estimated. Because the reflected light from the boundary is measured, the scattering noises coming from the turbidity of the tested medium can be greatly reduced. In addition, this method has some merits such as simple optical setup, high sensitivity, high stability, and suitability for a little amount of the tested medium in its native state (without dilution).
High-sensitivity sensor based on surface plasmon resonance and heterodyne interferometry
(2003-07-01)
Wu, CM
;
Jian, ZC
;
Joe, SF
;
Chang, LB
;
交大名義發表
A common-path, heterodyne interferometric system for investigation of the phase variations under surface plasmon resonance (SPR) is presented. With the combination of SPR and total internal reflection (TIR), the system has the merits of avoiding direction change in the output light and increasing sensitivity. The system utilizes a pair of orthogonally linearly polarized beams with heterodyne frequency of 60 kHz as the light source. Because the two beams are perfectly collinear, the noises resulting from the ambient conditions are greatly reduced. Compared to reflectivity variation measurement, which is widely used in traditional SPR, the phase variation measurement using commonpath, heterodyne techniques is approximately an order of magnitude higher in sensitivity and thus can be used as a high-sensitivity-demanded biosensor. (C) 2003 Elsevier Science B.V. All rights reserved.
Improved technique for measuring refractive index and thickness of a transparent plate
(2003-10-15)
Jian, ZC
;
Hsu, CC
;
Su, DC
;
光電工程學系
;
Department of Photonics
The phase difference between s- and p-polarizations of a circularly polarized heterodyne light beam reflected from a transparent plate is measured. The measured data is substituted into the specially derived equations and the refractive index can be calculated. Next, the variations of phase difference between s- and p-polarizations due to the wavelength shift and the extraction of the plate in a modified Michelson interferometer are measured. Then, its thickness can be calculated based on the measured value of refractive index, the variations of phase difference, and the specified value of wavelength shift. (C) 2003 Elsevier B.V. All rights reserved.
Measurements of material refractive index with a circular heterodyne interferometer
(2005)
Jian, ZC
;
Lin, JY
;
Hsieh, PJ
;
Su, DC
;
光電工程學系
When a light coming from a circularly polarized heterodyne light source incidents on an optical material, a phase difference between s- and p- polarization components of the reflected light occurs. This phase difference can be measured accurately with the heterodyne interterometry. The measured data are substituted into the special equations derived from Fresnel equations, the refractive index can be estimated. This method bears both merits of a common-path interferometer and a heterodyne interferometer. The refractive indices of three optical glasses and two birefringent crystals were measured to show the validity of this method.