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.     

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.