Power spectrum analysis for optical tweezers. II: Laser wavelength dependence of parasitic filtering, and how to achieve high bandwidth
Power spectrum analysis for optical tweezers. II: Laser wavelength dependence of parasitic filtering, and how to achieve high bandwidth
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DOI：
10.1063/1.2204589
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发表时间：
2006-06-01
影响因子：
1.6
通讯作者：
Flyvbjerg, Henrik
中科院分区：
文献类型：
--
作者：
Berg-Sorensen, Kirstine;Peterman, Erwin J. G.;Flyvbjerg, Henrik
在典型的光镊检测系统中，捕获物体的位置由撞击在象限光电二极管上的激光确定。当激光器是红外线的，光电二极管是硅的，它们可以一起作为一个意外的低通滤波器。这种寄生效应是由于硅对近红外光的高透明度。在此，针对高达100 kHz的频率和750与1064 nm之间的激光波长，求解了解释该现象的简单模型[Berg-Sorensen，J.Appl.Phys.93，3167（2003）]。该解决方案适用于实验数据在相同的范围内，并证明给这个检测系统的光镊的带宽，准确度和精度，仅限于数据采集板的带宽和带通纹波，这里分别为96.7 kHz和0.005 dB。
In a typical optical tweezers detection system, the position of a trapped object is determined from laser light impinging on a quadrant photodiode. When the laser is infrared and the photodiode is of silicon, they can act together as an unintended low-pass filter. This parasitic effect is due to the high transparency of silicon to near-infrared light. A simple model that accounts for this phenomenon [Berg-Sorensen , J. Appl. Phys. 93, 3167 (2003)] is here solved for frequencies up to 100 kHz and for laser wavelengths between 750 and 1064 nm. The solution is applied to experimental data in the same range, and is demonstrated to give this detection system of optical tweezers a bandwidth, accuracy, and precision that are limited only by the data acquisition board's bandwidth and bandpass ripples, here 96.7 kHz and 0.005 dB, respectively.