High-precision Measurements Of The Quartz Crystal Birefringence Dispersion Relations

With the development of polarizing technology and information technology, Polarizing devices designed by birefringence phenomenon have being applied in many fields. The refractivity of crystal is one of the most important optics parameter, the measurement of refractivity is vital to design device. There are many methods to measure birefringence, but they usually applicable for single wavelength and birefringence is obtained by primary refractive index, precision generally is 10-4 The accurate method is interferometry, for example, steep interferometry and self-compensation interferometry, they have a common characteristic that the precision can increase one or two order, but they are only applicable for visible light and sample precision demand is high, crystal techniques is difficult to meet, so measure precision is far from theory precision.We collate two methods of high accuracy to measure the dispersion of birefringence of quartz-polarization interfering measurement and ellipsometry measurement. Both measurement shield instability of the light source and have many attractive features:high accuracy, broad spectral range, convenient survey, automatic measurement and so on. The paper includes five sections.In the first chapter, the concept of birefringence and the present research situation of birefringence measurement are introduced and the main work of this thesis are described.In the second chapter, we give the theories of birefringence and the application of birefringence phenomenon. Then we divide the polarizing devices based on birefringence theories into three series and give a general description.Chapter three introduces continuous polarization interfering measurement. In this chapter, we collate the principle, the experiment, the result and the error analysis of polarization interfering measurement.In the fourth chapter and fifth chapter, we put forward two new methods to measure the birefringence of quartz by ellipsometer. These chapters are corn and the most important parts of this paper.Chapter four introduces the transmission ellipsometry. Phase retardation of quartz wave-plate with known thickness is measured under transmission mode of ellipsometer. Then the value of crystal's birefringence is calculated out. Error analysis is also given. The result shows that the method is easy and convenient and shields instability of the light source. Its accuracy is up to 10-6. Compared to the practical and reliable continuous polarization interfering, the accuracy can be improved an order of magnitude. Meanwhile, dispersion of crystal's maximum birefringence is measured continuously. The method can also be used to study dispersion of other birefringence crystal. This chapter describes the principle, the experiment, the result and the error analysis of birefringence measurement by the transmission mode of ellipsometer in detail. And the experimental data and curves of birefringence of quartz which changes with temperature is given.Chapter five introduces the reflection ellipsometry. Under ellipsometer reflection mode, the principle of birefringence measurement is conducted by Fresnel formula. And the experimental calibration method is described. The main innovations of this article:Fist, the measurement accuracy is improved by the development of the experiment of measuring the quartz's birefringence by ellipsometer.Secondly, the birefringence of quartz is measured based on the Measurement of retardation by ellipsometer. It turns out that the birefringence measurement accuracy is up to 10-6,higher than the measurement accuracy by polarization interferometry.Thirdly, the formula, principle is deduced to measure the birefringence dispersion of quartz under reflection mode of ellipsometer, while the calibration is introduced.