光镊研究双折射粒子的光致旋转和粒子的扩散特性-光学专业论文.docxVIP

．!里登鲎壁查叁兰型!：兰笪燕塞一 ．!里登鲎壁查叁兰型!：兰笪燕塞 一 塑塞 Abstract Optical tweezers，immediately after its invention，has been extensively used as a manipulation tool for micro—particles in many scientific fields．Due to this very special tool，the new experimental research method on地e behavior of an individual particle was devetolxe(1 tO understand the microscopic mechanism of macroscopic behavior of huge number of particles，whi穗was carried out in the traditional experimentaI research．How to develop new techniques，new methods and new applications of the optical tweezers is always an important research topic．In this thesis，the following two projects relevant to the application ofoptical tweezers were carried OUt， In the first part of this thesis．the principle of optical rotation due to the transfer of spin angular momentum from ii彝to particles t％pped by Optical—Tweezers was discussed by analyzing the interaction between the beam of light and birefringent crystal particles+The experimental method was developed to monitor and measure the optical rotation of crystalline CaC03 micro·particle in optical tweezers formed with an elliptical polarized light beam．The dependence of the rotation frequency of the trapped particle on the laser power,the ellipticity ofincidence laser and the geometry character of particles was analyzed and experimentally studied．The results of this work will be useful for effectively controlling the optical rotation，which provides a new controlling on angular dimension in addition to position control in three dimensions and makes the conventional optical tweezers have much better manipulated performance．Moreover it provides necessary knowledge for practical aeplication ofoptical rotation。such as optical micro—motor． In the second part，the Brownian motion characters of particles constrained between two shortly separated fiat walls was studied using video microscopy combined with optical tweezers。The experimental method was improved in the work compared with the work