| Surface plasmon resonance sensing technology based on phase modulation is the current research hotspot for biochemistry,medicine and other fields at home and abroad.The heterodyne interference technique has the advantage of high measurement sensitivity,and the phase shift of p light drastically changes rather than s light when the surface plasmon resonance occurs,so the collinear heterodyne interferometry system is constructed.In this paper,a high sensitivity surface plasmon resonance sensor based on phase modulation is constructed by use of a collinear heterodyne interferometer system and a Kretschmann configuration,to study the simultaneous measurement of the phase and the Goos-H?nchen displacement,and it can sense the sample with a small change in the refractive index by measuring the phase or the Goos-H?nchen displacement.These studies have important theoretical significance for studying the correlation between phase change and Goos-H?nchen displacement enhancement,and have practical application value in optimizing and improving the existing detection method of surface plasmon resonance based on phase modulation and designing micro nano-waveguide type optical device.The main research contents are:(1)based on the light electromagnetic theory,the polarization state,total reflection characteristic and surface plasmon resonance sensing theory are discussed,including the evanescent wave,Goos-H?nchen displacement and its relationship with polarization state,attenuation total reflection,the transmission characteristics of light in the metal,the conditions of occurring surface plasmon resonance and the Kretschmann configuration;(2)the polarization display of light and its application in elliptically polarized light measurement are analyzed,including polarization display principle,the display of polarization direction and elliptically polarized light measurement experiments;(3)the elasto-optical effect,elasto-optic coefficient,the normal and abnormal Bragg diffraction and the basic structure and working principle of acousto-optic modulator are expounded;the digital linear voltage control technology of the acousto-optic modulator driving source is studied,and the driving voltage and 1st order diffracted optical power are measured;(4)the Bragg diffraction experiment system is constructed,the amplitude,frequency,polarization characteristic and diffraction characteristics(influence of diffraction order and frequency drift)of the molybdate lead acousto-optic modulator are studied,the effects of light intensity modulation and beam drift on the phase characteristics of heterodyne measurement system are analyzed.Based on this,the collinear laser heterodyne measurement system with dual acousto-optic modulator is constructed and the phase characteristics and the calibration of Soleil-Babinet compensator are studied experimentally;(5)the surface plasmon resonance technique enhanced the Goos-H?nchen displacement based on the Kretschmann configuration,and the Goos-H?nchen displacement is simulated by the prism waveguide structure.The experimental system of collinear heterodyne surface plasmon resonance based on phase modulation is constructed and the phase measurement experiment is completed.On this basis,the method of simultaneous measurement of phase and Goos-H?nchen displacement is studied.Its main innovations are:(1)the 256-level gray-scale linear acousto-optic modulator drive source is fabricated to improve its linearity,including acousto-optic modulator drive source,microprocessors,electronic analog switches and linear voltage compensation technology;(2)the single-beam orthogonal polarization generating system with the beat frequency as “intermediate frequency difference” is studied combining with the dual acousto-optic modulation technique and the polarization splitting technique,collinear laser heterodyne measurement system is constructed,the phase characteristics and the calibration of Soleil-Babinet compensator are studied experimentally;(3)the Kretschmann configuration with a isosceles prism and its base angles near by the resonance angle is fabricated,and the Goos-H?nchen displacement of the prism waveguide structure is simulated;(4)the polarized visual ellipsometric measurement system is studied,which provides a new idea for constructing surface plasmon resonance phase ellipsometer measurement system based on CCD;(5)The method of simultaneous measurement of phase shift and Goos-H?nchen displacement is studied and it has a positive effect on optimizing and improving the existing detection method of surface plasmon resonance based on phase modulation. |
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