| The transmission characteristics of light in inhomogeneous medium have been widely used in the fields of atmospheric optics,laser communication,laser remote sensing,and the design and manufacture of graded index optical elements.However,there is always a certain degree of mystery to the phenomenon of light transmission.This was partly due to people from formation of the light straight line dissemination of the concept of "entrenched",on the other hand is in the visible range of daily life,rarely directly observed phenomenon of the bending of light transmission.The application of light in inhomogeneous medium in the design and manufacture of atmospheric laser communication and gradient refractive index optical elements is needed to study the relationship between the size of the refractive index change gradient and the refractive index gradient in the process of light transmission.But by a variety of factors,has been in the laboratory scale within the air cannot establish a relatively stable large gradient temperature field,so that in the laboratory limited space,cannot achieve the gradient medium light bending transmission characteristics of the experimental study.At the same time,it is very difficult and expensive to prepare large scale gradient refractive index material by artificial method.This has become the main bottleneck technology developed experimental system of optical transmission characteristics in inhomogeneous medium,causes the student to the light by imagination or watching courseware illustration in the inhomogeneous media transmission characteristics of understanding,there is not an instrument,can be used to study the students’ laboratory optical transmission characteristics in inhomogeneous medium.In order to meet the needs of experimental research on the transmission characteristics of light in no uniform media,the development of "optical transmission characteristic experiment system in gradient refractive index medium" has been carried out in the laboratory.The experimental system uses a semiconductor cooling plate immersed in water to establish a gradient temperature field which gradually decreases from top to bottom in water.Based on the thermo-optic effect,the gradient refractive index field is gradually increased in the water from top to bottom.The experimental system consists of light source,gradient temperature field and temperature field real-time measurement of three parts and the experimental instruments are mainly semiconductor lasers,transparent plexiglas sink,semiconductor cooling film,distributed temperature tester.The experimental system composed of them has the advantages of simple structure,low cost and easy popularization.Aiming at the shortcomings of the existing "vertical gradient index optical transmission experiment system characteristics in the water tank of medium high temperature gradient area,studies the linear temperature gradient region by setting the vertical partition plate on one side of the semiconductor refrigeration piece is increased in the vertical direction,and achieved a certain effect,the bending phenomenon of laser beam trace level the incident is more significant.The experimental results show that the gradient refractive index field formed in water has a large vertical scale,good stability and can be reused.In order to solve the problem of measurement of laser beam track in water,we have designed a kind of non-contact measurement method of laser beam track.According to the characteristics of the experimental device,we designed a kind of transparent coordinate plate and beam track measuring device.The transparent coordinate plate is placed on the side wall of the water tank,and the beam trajectory coordinates are determined by the beam track measuring device.The non-contact measurement of the laser beam track is realized,and the measurement accuracy is achieved.Based on fermat principle and the principle of hot light effect,we established the track equation of laser beam transmission in this experimental system.The experimental results are in good agreement with the calculated values.Based on the experimental results of optical transmission characteristics in gradient temperature field,this paper also proposes a method to realize the direction of heat transfer and process visualization by optical means,and design the experimental device to demonstrate the direction and process of heat transfer.For the first time to achieve the heat transfer direction and process of real-time visualization demonstration.Using this experimental system,both qualitative observation of laser beam transmission medium in the track gradient index,and quantitative analysis of the incident laser beam and refractive index gradient direction and the angle between the refractive index gradient effect on the beam track.In this paper,the "experimental system of optical transmission characteristics in gradient refractive index media" and the "real-time demonstration instrument of heat transfer direction and process" can be used as the expansion of optical experiment teaching for undergraduates such as physics,engineering thermo physics and optical communication Instrument,but also for the atmospheric optics,heat transfer,atmospheric laser communications and optical remote sensing and other professional graduate students to provide experimental simulation conditions,but also as a science and technology museum science display equipment. |
