光镊系统中微小颗粒的位移和所受力的测量

利用高稳定度的并配备了高精度位移和力测量装置的光镊系统，实现了对微米颗粒的纳米量级的位移和所受皮牛顿量级的力的定量测量.     

聚苯乙烯微粒光子晶体的反常透过特性

在实验上发现了3μm聚苯乙烯(PS)小球光子晶体在350nm至900nm波长上的透过率的周期扰动.根据透过率曲线的周期扰动的峰谷值判断，这种周期性透过率特性是基于PS小球的whispering-gallery-mode(WGM)共振，而不是源于米氏散射或布拉格衍射.实验表明，周期性排列 小球在非带隙区域对光的传输同样有一定的影响.这一结果对光子晶体薄膜的应用提供了新 的可能性. 关键词： 光子晶体 透过率 whispering-gallery-mode共振     

Effects of matrices on Mie scattering in the mid-infrared region

Various Mie scattering systems, each having a transparent matrix, are studied in the mid-infrared region. Our three theoretical scattering systems correspond to a lossless scatterer, an anomalous dispersive dielectric scatterer and a metal scatterer, each in a non-air usual matrix. The refractive-index effects of the matrix on scattering and extinction efficiencies in the mid-infrared region are found to be quite different in different cases. Although the non-air usual matrix reduces scattering and extinction efficiencies in the first kind of system, it may or may not help scatter and extinguish the mid-infrared radiation in the second, and it has little effect on them in the third.     

EFFECT OF SPHERICAL ABERRATION INTRODUCED BY WATER SOLUTION ON TRAPPING FORCE

Trapping force of an optical tweezers system with an oil immersion objective is calculated with a ray-optics model. Results indicate that the trapping force will be decreased as a result of the introduction of spherical aberration, which is caused by the refractive mismatch between objective oil and water, when the sample manipulated is suspended in a water solution. The effect of spherical aberration will be serious when the detection depth of the optical tweezers is enhanced.     

Measurement of Binding Force between Microtubule-Associated Protein and Microtubule

Microtubule-associated proteins （MAPs） are important proteins in cells. They can regulate the organization, dynamics and function of microtubules. We measure the binding force between microtubule and a new plant MAP, i.e. AtMAP65-1, by dual-optical tweezers. The force is obtained to be 14.6 ± 3.5 pN from the data statistics and analysis. This force measurement is helpful to understand the function and mechanism of MAPs from the mechanical point of view and lays the groundwork for future measurements of the mechanical properties of other biological macro-molecules.     

光镊在生命科学中的应用

由于光镊具有无直接接触、无损伤等诸多优点,且光镊产生的力在皮牛顿量级,正好落在生物大分子相互作用力的范围,所以光镊在生物大分子相互作用测量方面取得了越来越广泛的应用.文章详细介绍了光镊的出现、发展过程以及在生命科学中代表性应用结果.这些结果表明,将光镊应用在生命科学领域,可以揭示或证实许多以前不曾深刻了解的生物大分子的活动规律与机制.     

四象限探测器位移测量的标定方法

提供了一种能实时快捷地对光镊系统中四象限探测器位移探测信号进行校准的方法.实验研究表明了该方法的可靠、精确,其自身的不稳定性小于1％.利用该方法研究了校准系数随小球深度的变化情况,得出校准系数随小球深度的升高而减小.该方法可以用于光镊系统稳定性的监测.