Optimum Design And Performance Analysis Of Broadband Reflective Film And Induced Transmitted Filter

With rapid development of the national economy and various Hi-tech equipment,optical films have been found more and more applications in many fields. This paper focuses on the design of high-reflective coatings and induced transmission filter and analyzes their optical performance.The broadband high-reflective coatings is of important application in the fields,including cosmic physics, life sciences, synchrotron radiation, atomic structure analysis,nano-devices, atmospheric physics, space communication, lithography, laser medical equipment, positioning and monitoring system, weapon system, et al. Currently, there are some key problems about the broadband high-reflective coatings, such as the limit of the refractive index of the material, the dissatisfaction of needs for higher reflectance and wider reflective bandwidth, and the uncontrolling of the accuracy of the the thickness and the refractive index of the layers in the preparation process. Thus, in this thesis, to satisfy the requirements of optical elements for wide spectral reflection, the reflection wavelength region of the coatings was widen by using multiple stacks and other designing method. The design and optimization was based on the software of TFCalc. By improvements and adjustments continuously to the coatings structure parameters, many high-reflective coatings with different incident angles of 0° and 60° were designed, and the bandwidth of the coatings includes 115~220nm、220~400nm、400~900nm,900~2000nm and 450~14000nm, and their performances were analyzed. The result shows that the reflectance of these high-reflective coatings within supper broadband bandwidth reaches a very high level, comparing with increasing series structure coatings, period structure coatings can reach higher reflectance using less layers, and incident angle has less influences on metal coatings than that on dielectric coatings. In order to satisfy the requirement of bandpass filter for broadband stopping, by using the method of induced transmission,a induced transmission filter was designed. Its central wavelength is 550 nm,its biggest transmission is 74.8%, and its half-width is 3.5nm. The result shows that the performance of the induced transmission filter is great; the increasing of the incident angle has a bad influence on the bandpass filter, so the incident angle is not allowed to exceed 10°when using it.