光镊系统中光放大倍数对测量结果的影响

从实验和理论两方面，讨论了在光镊系统中，光放大倍数在500—1000倍、间隔为100倍的范围内，对四象限探测器位移测量信号的幅值及其线性度的影响.实验结果与理论结果符合很好，得出相同的结论：当微粒的影像半径约为四象限探测器探头半径(50—60)%时，可以得到幅值大、线性好的输出信号. 关键词： 光镊系统 放大倍数 四象限探测器

Effect of optical magnifications on the displacement measurements in optical tweezers system

The effect of different optical magnifications on the amplitude and linearity of displacement signals measured by the photodiode quadrant detector in an optical tweezers system is studied both experimentally and theoretically. Based on the experimental results we find that the output signal with larger amplitude and more preferable linearity can be obtained when the magnified images of α particle have diameters of 50% to 60% of the detector diameter. Theoretical calculation confirms it.