| Optical Phase Retarders are not only important optical components in laser technique and polarized light technique fields,but also the basic optical phase modulators that introduce a phase shift between orthogonal and linearly polarized component when light transmits through them.The common are quarter-wave plate and half-wave plate.Fitted with other polafimetric elements,they can realize converting and rotating of polarization states,and modifying of all kinds of light wave.So we can say that everywhere use polarized light technique can hardly work without optical phase retarders.Conventional optical phase retarders are mostly designed by birefringent material.The refractive indices depend on the wavelength so strongly that the retardation is close to wavelength,here we call this dependent relationship the birefringent dispersion of material.This is the reason why conventional optical phase retarders are mostly applied to a single wavelength but can' t be used to varied wavelength,so they are inconvenient to handle.Therefore somebody put forward the design of achromatic optical phase retarders whose retardation are insensitive to wavelength.Due to the less dependence on wavelength,this kind of optical phase retarders have an extensive used perspective.Achromatic optical phase retarders can be made by different methods and by miscellaneous design forms,while the common aim is to improve the achromatic spectral range and precision. Achromatic optical phase retarders can be divided into two main types according to design mechanics,birefringence and total internal reflection.The simple fiat-plate birefringent ones have been proved to be ideal by experience.Considering the contribution of other factors,to improve design accuracy,avoid optical path deviation,reduce insert dissipation and increase the manipuility of the device is our purpose.Because some wave plate manufactures are quite thin,the superficial is smooth and its index of surface reflection is high,interior of the wave plate as well as between the compound wave plates have the interference which the light beam reflects many times causes.(zero order mica 1/4 wave plates,its thickness is between 0.032-0.035mm,such a thin thickness will probably cause transmitted light to have intense interference).These shortcomings will affect the retard quantity of wave plate,transmissivity and so on,will then affect the compound wave plates' uses.Although at present the theory of unit wave plate and the compound wave plates as well as the experiment is quite mature,but it has not considered interior plate,as well as between the wave plate the multi-light beam reflection which causes the interference influence.For the better use of wave plate,and enhancing the the performance of wave plate(unit wave plate, compound wave plates and so on),the research of unit wave plate's interference effect is meaningful.At present,there are some methods such as the photoelectricity modulation method,the compensation method and the spectrographic method and so on.But some methods are too complex,some can only been used to measure the phase delay of 1/4 wave plate.What's more, many methods can only measure the phase retardation at a single wave length and cannot obtain the result as the wave length changes.In view of this question,this article put forward one ellipsometric spectrum method which can measure the wave plate's phase retardation in a certain spectrum range.This method has the following merits:convenient survey,the periodic time is short,high accuracy.In 1945,A.Rothen designed and described the first elliptical polarization measuring instrument,used to measure and the research the thin film's surface optical quality(for example refractive index and thickness).From now on the elliptical polarization survey technology has been applied to more and more widespread field.The ellipsometer also obtained a considerable development.The original manual survey turned into automatic survey,the spectrum scope gradually broadens,the measurement accuracy becomes more and more higher.This thesis use the UVISAL ellipsometer which is produced by the French Jobin-Yvon Corporation to measure the phase retardation of quartz wave plate and mica wave plate in a certain spectrum scope.What the experiment uses is the transmission type of this ellipsometer.The full text has the following several aspects.The first chapter mainly introduced the selected topic basis,the purpose,my work as well as the significance.The second chapter introduced the unit wave plate's basic theory,and introduced two kind of commonly used wave plates,the quartz and the mica and the elementary knowledge of the two material.The third chapter introduced the light interference theory,the medium membrane's interference theory,and inferred and analyzed the theory of the wave plate surface coherent reflection to retard the quantity and the transmissibility influence many times.The fourth chapter,surveyed the law using the ellipse to give the quartz wave plate and the mica wave plate's in certain spectral region detention quantity from the experiment along with the wave length change,has given the quartz wave plate and the mica wave plate's in certain spectral region transmissivity using the UV-3101PC spectrophotometer along with the wave length changes.Originality innovation places:Inferred the interference theory of the unit wave plate with the matrix method,which the multi-light beam reflection caused,namely inferred single wave plate's phase delay quantity,luminous intensity transmissivity formula,as well as wave plate's phase delay quantity and transmissivity relationship after considering the multi-light beam reflection which caused the interference,.Selected one kind of precision measuring wave plate to retard the quantity the method,and has obtained the quartz wave plate and the mica wave plate's precise detention quantity.After having surveyed on the wide band anti-reflection film,we also obtained the wave plate's precise detention quantity.We provided the very good theory basis in the present paper for the design and the use of the unit wave plate,the compound wave plates,and for further enhancing the compound wave plate's performance to establish the theory basis,therefore our research work had certain reference value for use.Through the above work,the author thought that from now on we may study dual,three Yuan wave plates' interference effects,because dual,three Yuan wave plates involve the interference which causes multi-light beam reflection between wave plate's.It will make the work more perfect,and it may make a bigger breakthrough. |
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