| Polarizers, one of the most important optical modulators, are widely used in modem laser action technique, optical information processing, image-forming system, etc. The function of polarizers is to transform non-polarized light into polarized one, which is the preparation for further modulation. With the sustaining development of modern optics, especially the emergence of laser, polarizers are becoming more and more widely used. Noteworthily, laser-polarizing prisms suitable for laser use emerge. Because of their fine extinction ratio and high anti-light-damage threshold value, laser-polarizing prisms are popular among workers in science and technology field. There are many types of laser- polarizing prisms, according to using conditions. In spite of their difference in the form of design, they are the optimum design based on a few kinds of prisms in common use. Several parameters are required to describe their performance, some of them have been studied home, and there are also others, due to the limitation of study, was not researched profoundly enough. Light transmission, an important parameter of polarizing prisms, is one of them. Only the main transmitted light from the glued layer or the first-order transmitted light also, is considered at most in the existing study outcome about light intensity transmission. On occasion, some experimental results about light transmission are given as a performance index. And nearly no one considers the contribution of the higher-order transmitted lights and the effects of the inaccuracy in glue technology on light distribution.The thesis emphasis on the study of light transmission and emergent light distribution of laser polarizing prisms with typical forms of design. The original work in the thesis lies in the thorough research of the factors that effect light transmission and distribution; otherwise, corresponding experiments are designed and conducted. Generally, the main content is as follows:In the introduction, we summarized the fields of application, materials used and the primary forms of design of crystal polarizing prisms. The present research correlative to this field, the source of this research subject, and the necessity of the research are also introduced. In the second chapter, firstly, we introduce part of the basic theory and the design principal of crystal polarizing prisms; then we have a summary to the design of Nichol prisms, which are important in history and introduce the design of Glan type crystal polarizing prisms in detail.In the third chapter, basing on light interference theory, we discuss multiple-beam interference and equal thickness interference, which are also the base of our main research. According to the structural feature of polarizing prisms, we transform the parameters related to the structure of prisms into geometric model, and use this model to solve the problem of the relation of different angles. Along with Fresnel formula and multiple-beam interference, we get the formula of light transmission. This formula shows the change of the light transmission with the continuous change of incident angle and azimuth angle of incident light, and the refractive index of the glue and thickness of the glued layer of the prisms. The effect of wavelength is also studied. The outcome suggest that, firstly, the change of light transmission with the continuous change of parameters is periodic; secondly, as far as the degree of effect is concerned, the light transmission of air-spaced prisms is much more sensitive to the change of the parameters than that of the glue spaced ones; thirdly, as to the prisms glued with the same dielectric, the effect of prisms whose optical axis parallels to the glued layer is intense than those whose optical axis parallels to the plane determines by the normal of incident face and that of the cut face.The fourth chapter describes the experimental system we design. Using the relation formula of angles we get in chapter three, a formula of light transmission corresponding to the experimental system is... |
PDF Full Text Request