Optical trapping based method for in-situ calibration of displacement of piezoelectric platform

Abstract

The invention provides an optical trapping based method for in-situ calibration of displacement of a piezoelectric platform. High-precision detection of motion displacement amplitude and frequency of the piezoelectric platform can be realized by analysis of position signals of Brownian motion of standard-size globules trapped in an optical trap system. Besides detection of the piezoelectric platform, standard particles are trapped by laser under microscopic imaging, and position motion signals of the particles are quickly detected by a detector. The piezoelectric platform sends low-frequency fixed-amplitude motion signals to drive a sample chamber to move, the particles trapped in a light trap is subjected to actions of fluid periodic viscous resistance, and voltage proportionality coefficient of a position sensitive detector can be calibrated by detecting the motion signals of the particles. The piezoelectric platform sends signals to drive the sampling chamber to move again, a power spectrum of the trapped particles is analyzed, a peak of the power spectrum is compared with background thermal noise to invert real motion displacement amplitude of the piezoelectric platform, and frequency of the peak stands for motion frequency of the piezoelectric platform.

Description

technical field [0001] The invention belongs to the technical field of optical high-precision displacement detection and optical micro-manipulation, and in particular relates to a method for in-situ calibrating displacement of a piezoelectric platform based on optical capture. Background technique [0002] Piezoelectric stages are widely used in instruments that require precise control of displacement, such as biological microscopes, optical tweezers, and atomic force microscopes. The piezoelectric platform has the precision of nanometer movement, but in actual use, due to the influence of various factors such as the environment and fixed coupling parts, the movement amplitude of the fixed parts or samples carried by the drive will deviate from the nominal value of the instrument drive. It will lead to larger errors when the piezoelectric platform is used as an accurate measuring instrument to calibrate other signals. For optical tweezers and atomic force microscope systems...

AI Technical Summary

Problems solved by technology

However, in actual use, it is difficult to use this method to calibrate the motion range of the sample chamber on the piezoelectric platform. For example, the motion range of the piezoelectric platform is affected by the motion process and motion direction.

Using the image method of detecting the movement amplitude of sticky particles, the detection accuracy depends on the accuracy of the particle position, and it is difficult to analyze the movement of particles at higher frequencies

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