Light Phase Delay Measurement Methods And Technology Research

In the application fields of polarizing technology and information technology, the opticalphase retarders are important components in optical modulation system. They can produce aspecific phase retardation of incident polarized light to a specific wavelength or a wavelengthrange, which make the incident light polarization state change. Phase retarder can achieve thelight polarization state conversion or the plane of polarization rotation used with other polarizeddevices. Wave-plates are the main optical phase retarder which can be divided into singlewave-plate and the composite wave-plate. They are widely used in precision opticalmeasurements, optical modulation and measurements of biomedical and other fields. Its mainoptical technological parameter is the phase retardation; it has a direct relationship with themeasurement of light wavelength. The retardation measurements in a specific wavelength have anumber of ways, such as the compensation method, the electro-optic modulation, opticalheterodyning,1/4wave-plate method. Although the principle of these methods, the degree ofdifficulty to achieve and complexity of the system are quite different, they can basically meet theneed for single wavelength measurements. The accuracy of the wave plate, in the case of therapid development of technology of laser and polarized technology, also increasing, whichrequires not only the accuracy of measuring the retardation but also the diversity and the ease ofthe metrical methods.Refer to reference literature, wave plate retardation of wide spectral measurements havebeen a difficult problem, previous researchers have discussed birefringent material of thepolarizing interference spectrum, it was mainly for the study of material properties and did notgive the phase retardation of the device corresponding each wavelength within the measuringrange. In this paper, through the measurement and analysis of continuous polarizationinterference spectrum of a single quartz wave plate, we found that the spectrum included notonly the material properties such as absorption and birefringence but also wide spectral rangeoptical phase delay information which proposed a new measurement and analysismethods. Further using this new approach, its application to measure the retardation ofachromatic composite wave plate was tested, Theoretical analysis and simulation showed thatcontinuous polarization interference spectrum described accurately, clearly, easily the achromaticcomposite wave plate parameters, especially for the guidance of wave plate processing to detectand choosing to use the device, the method has a very important practical significance. Thispaper is divided into the following chapters to elaborate.The first chapter, the developing history and the research actualities of the wave plates andthe phase retarders’ measurements was introduced. This chapter also described the paper’s content, purpose and meaning.The second chapter introduces the basic knowledge of the wave plate and polarization.Firstly, though principle of the wave plate retarder, we detailed introduced the main properties ofthe different wave plate. Secondly, knowledge of polarization and polarized light and severalformulation descriptions in polarized light was introduced.The third chapter introduced several common optical phase retardation measurementmethods, including: polarization interference method, compensation method, ellipsometrymeasurements.The fourth chapter, based on the common phase retardation measurement methods,proposed a theory of continuous polarization interference measurement to overcome broad-bandmeasurement deficiencies. The method used double light alignment measuring method of theShimadzu UV-3101pc spectrophotometer to increase the stable reliability of the data collection,and get the continuous polarization interference spectrum of the quartz wave plate for the knownthickness of300nm-800nm wave band. The analysis shows that the experimental curve andtheoretical curve fit well, and the measurement of the average error is less than2o.The fifth chapter, based on continuous polarization interference in the use of measuringsingle-wave plate, proposed the idea of measuring the achromatic wave plate. Throughexperimental simulation, experimental and theoretical values coincided very well. That provedthe validity.The main innovations of this paper:First, According to the principle of continuous polarization interference, we proposed a newmethod to measure the wide-band phase retardation variation of the quartz wave plate, and thedata processing method for the corresponding retardation variation of each wavelength.Second, we theoretically discussed the feasibility of measuring the phase retardation ofachromatic composite wave plate by polarization interference spectrum. Through simulation andverification, the experimental curve and theoretical curve fit well. It proved that the method iseffective. This laid the foundation for the achromatic delay device research.