Y. Ren, Min-Cheng Zhong, Jianguang Wu, Ziqiang Wang, Yin-mei Li
{"title":"Experimental Investigation on How Sampling Frequency Affects the Measured Stiffness of an Optical Trap","authors":"Y. Ren, Min-Cheng Zhong, Jianguang Wu, Ziqiang Wang, Yin-mei Li","doi":"10.1109/SOPO.2009.5230139","DOIUrl":null,"url":null,"abstract":"The stiffness of an optical trap is an extremely important parameter in measuring mechanical properties of biological micro-particles or colloids. Few attentions are paid to experimental study of the stiffness v .s. sampling frequency dependence. We studied experimentally how the sampling frequency of a detector influences the measured transversal stiffness of a single beam optical trap. The stiffness of an optical trap was calibrated by detecting the reflected light signal by polystyrene spheres through a quadrant photodiode detector (QPD), and then calculated using the Boltzmann statistics method. In our experiments, polystyrene spheres had been used to conclude that in the directions both parallel (p) and perpendicular (s) to the laser polarization direction, the measured stiff-nesses are different and all varies with the sampling rate of the QPD used in our experiment. For a certain sampling frequency range, the measured stiffness decreases while the sampling frequency increases. Our results provide researchers information for sampling frequency selection in related experiments.","PeriodicalId":6416,"journal":{"name":"2009 Symposium on Photonics and Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2009-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2009 Symposium on Photonics and Optoelectronics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/SOPO.2009.5230139","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1
Abstract
The stiffness of an optical trap is an extremely important parameter in measuring mechanical properties of biological micro-particles or colloids. Few attentions are paid to experimental study of the stiffness v .s. sampling frequency dependence. We studied experimentally how the sampling frequency of a detector influences the measured transversal stiffness of a single beam optical trap. The stiffness of an optical trap was calibrated by detecting the reflected light signal by polystyrene spheres through a quadrant photodiode detector (QPD), and then calculated using the Boltzmann statistics method. In our experiments, polystyrene spheres had been used to conclude that in the directions both parallel (p) and perpendicular (s) to the laser polarization direction, the measured stiff-nesses are different and all varies with the sampling rate of the QPD used in our experiment. For a certain sampling frequency range, the measured stiffness decreases while the sampling frequency increases. Our results provide researchers information for sampling frequency selection in related experiments.