Design & Construction of Circular Polarization Interferometer via Surface Plasmon Resonance
Date Issued
2006
Date
2006
Author(s)
Jan, Chia-Ming
DOI
zh-TW
Abstract
Circular polarization interferometer detets phase difference by means of utilizing one set of circular polarization beams to produce a 90°output phase delay. When TE wave and TM wave passed a quarter wavelength-plate, we used two polarization beasm spitters, and hope to bring ninty degree phase difference for output signals. Then we can directly calculate the phase difference from function of arctangent of the two orthogonal differential signals. Under the scheme of circular polarization interferometry, we can prevent interruption from high frequency electronic noise, and reduce system volume. Moreover, it can cancel out the DC term of interference fringes which cause low visibility. Furthermore, we recommend a full new scheme for interferometry — P-S common beams— to let the path difference between TE & TM waves be equal. It is powfully benefit for resolution of optomechnism.
Surface plasmon wave which can be excited between metal and dielectric layers is a wave propagation phenomena caused by the charge density of quantum resonance on the boundary. There is an evanescent field forming on surface plasmon angle while light beam impinges onto the interface. The electric field decays toward both side of the interface exponentially. The phase and intensity of TM reflective wave would change significantly at this moment. Beginning with the basis of electromagnetic theorem, the relationship between intensity, incident anlge, phase of TM reflective wave and dielectric constant could be derived. However, surface plasma resonance does not affect TE wave. We can obtain the light intensity, phase, resonance angle, and resonance wavelength in accordance with different effluence affected for TE & TM wave. These well developed interrogation techniques have been widely applied in measuring the thickness variation of thin film, the reflective indeices change of liquid or gas samples and the biomolecular interaction.
During the course of this study, we extended our research team’s many years optical system design experience and employed a paraboloidal mirror, a spherical mirror, and a precision servomotor control on circular polarization interferometer. We successfully develope a small volume, low cost, phase and angle interrogation circular polarization interferometer with wide range of dynamic measurement. Using Lissajous curve from two orthogonal signals, we could modify metered intensity. After measuring various concentrations of glucose standard solutions (100 mg/dL ~ 20000 mg/dL), the system has been proved to have 10-4 resolution in measuring reflective indices. By the assay of different concentrations of anti-CRP and CRP, the study verifies the system has the ability of biomolecule specific interaction detection which is even better than angular interrogation SPR instrument. The success of the IgG and anti-IgG for antigen-antibody combination proves the capability of BIA experiment of the system for biomedical detection.
Subjects
表面電漿共振
圓偏光干涉
相位調制
C—反應蛋白
surface plasmon resonance
circular polarization interferometry
phase-interrogation
CRP
Type
thesis
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