Development Of An Experimental System For Optical Transmission Characteristics In Gradient Refractive Index Media

The characteristics of light transmission in inhomogeneous medium has been extensive used in the large-scale field, like atmospheric optics, atmospheric laser communication and so on; it also been widely used in the optical components design and manufacturing of miniature gradient refractive index. For the phenomenon of bending of light transmission, there is always some degree of mystery. On the one hand, from the impressive concept of the light rectilinear propagation; on the other hand, in the visible range of daily life, it's not easily observed phenomenon of the bending of light transmission.The bending properties of light transmission in inhomogeneous medium have been applied in space laser communication, the design and manufacturing of optical element and optical measurement method in mass transfer of heat transfer. In the further study of light transmission, need to know the relationship between the gradient magnitude and direction with the light track or the light spot drift. But restricted by many factors, relatively stable and large gradient temperature field in the air of laboratory cannot be established. Therefore in the limited space of the laboratory, cannot realize the experimental research of light bending transmission characteristics. At the same time, the artificial preparation of large scale solid gradient refractive index materials are extremely hard, cost is extremely high. This has restricted the study about the experimental system of the light in inhomogeneous medium transmission characteristics, so the students understanding of light transmission characteristics in gradient refractive index medium, the more dependent on the class icon and their own imagination.Based on the above problems, and considering the limitations of existing technology and technology needs, this paper studies an "experiment system of optical transmission characteristics in gradient refractive index medium". Not only the system can qualitative observation light beam of transmission track in the gradient refractive index medium, but also quantitative research the relationship between the size and direction of the refractive index of medium with the beam path. This experimental system consists of light source, gradient refractive index field and the temperature measurement, experimental instrument is mainly used in semiconductor lasers, transparent water tank, semiconductor refrigeration piece, multi-channel temperature tester.This experiment system for Fermat principle and heat photosynthetic efficiency be basic principle. Using semiconductor refrigeration piece set up the gradient of temperature field, so the temperature gradually decreased from top to bottom. Due to the thermal effect of light, the water can form gradient of refractive index, where the refractive index gradually increase from top to bottom. What's more, there are linear inverse relationship between the gradient temperature field and gradient refractive index field. The gradient refractive index field large-sized and stability, so the propagation path of laser beam can be seen clearly and measurement accurately. The laser beam propagation path will occur bending in gradient refractive index field. By changing the laser beam incident Angle and the size of the gradient, that's can explore the relationship between the deflection of beam produced by the gradient field with the laser beam incident Angle and the size of the gradient field.When light propagation in inhomogeneous medium, it can produce concentrated phenomenon in the region of the low refractive index, the astigmatism phenomena in high refractive index region. Based on the propagation characteristics, this article also designed two experimental apparatus:"hot and cold water mixing process visualization and measurement of thermal equilibrium time" experiment device and "transparent liquid miscibility process visualization" experiment device. After transparent heterogeneous, the laser beam with certain divergence formed laser speckle on the screen. There are concentrated and astigmatism phenomenon when the light through in inhomogeneous medium. By observing the intensity change of laser speckle, it can determine the medium distribution within the heterogeneous medium.The biggest innovation of this experiment system is for the first time put forward and used the semiconductor refrigeration piece directly immersed in a liquid. Using the semiconductor refrigeration piece of cold and hot surface to absorb and heat the liquid, established of a large scale and high gradient temperature field in a liquid. Using this method to build gradient refractive index field in water, there are advantages of large scale, high gradient, good stability, reusable. This experiment system to meet the physical, chemical and engineering thermal physics, optical communications and other professional student experiment needs; or for atmospheric optics, laser communication and optical remote sensing technology such as experiment simulation studies provide conditions. It is of great significance.