【作者】 郝军；

【导师】 曹庄琪；

【作者基本信息】 上海交通大学 ， 光学， 2010， 硕士

【摘要】 当一束光入射到界面,几何光学认为入射和反射在同一点发生,只不过产生一个相移。但实际上却不然,古斯和汉欣在1947年作了一个实验,证明反射点离入射点有一段距离,这就是所谓的古斯-汉欣(Goos-H?nchen,简称GH)位移。这是由于入射光中不同的单色平面波分量具有不同的反射相移所造成的。在一般单层界面的情况下,GH位移通常只是入射光波长的量级,这使得它很难在试验中被观察到。在过去的二十年中,各种装置被用来增强古斯-汉欣效应,比如非对称双棱镜结构,半无限大弱吸收介质中的布儒斯特角处的反射以及光子晶体中的缺陷模式角等。事实上,当光入射到界面上时,电磁场能量渗透到第二层介质中并且建立一个迅衰场,在重新回到第一层介质中之前它会沿着界面传播一段距离。因而很自然的GH位移就与渗透深度成比例,如何有效地增加穿透深度进而方便GH位移的直接测量就成为了研究重点。在本文中,我们利用双面对称金属包覆波导中的超高阶模式,我们得到了毫米量级的GH位移,在进一步的研究中,我们发现当导波层厚度增大时,相应的GH位移也会增大。在对称双面金属包覆波导的基础上,我们提出了一个新型可调谐的光学滤波器,通过改变小孔的位置,我们可以调谐该滤波器获得想要中心波长。更多还原

【Abstract】 It is thought by geometric optics that the reflection point and the incidence point coincide with each other when a light beam impinge onto an interface, only a phase shift is introduced. But this is not the truth, Goos and H(a|¨)nchen made an experiment in 1947 which proves a lateral shift between them, this is so called Goos-H(a|¨)nchen (GH) shift. It is because each plane wave component of the incident beam undergoes a slight different phase change after total internal reflection.At a single dielectric interface, the GH shift is of the order of wavelength. The smallness of the shift for optical wavelengths had impeded its direct observation in a single reflection. In the past two decades, various schemes were proposed to enhance the effect, such as asymmetric double-prism structure, near the Brewster dip on reflection from a weakly absorbing semi-infinite medium, at the angle of defect mode of photonic crystals and so on.In fact, when a light beam impinges on the interface between two dielectric media, the electromagnetic energy of the incoming beam penetrates into the second medium and builds up an evanescent wave which would propagate along the interface for some distance before re-emerging into the former medium. The lateral displacement is then proportional to the penetration depth of the light field; the question resolves itself into how to effectively increase the penetration depth for direct measurement of the GH shift. In this paper, by using the ultrahigh order modes in a symmetrical metal-cladding optical waveguide (SMCW), we obtain tremendous GH shift greater than 1700 wavelengths, and in further investigate we show that the lateral displacement increases with the thickening of the guiding slab at the well excitation of ultrahigh order modes.A new tunable optical filter is fabricated based on the enhanced GH effect in the SMCW structure; we can tune the filter to get the desired centre wavelength through changing the position of the aperture.更多还原