Integrated optical fiber probe type near-field optical tweezers and method for measuring near-field optical trapping force by AFM (Atomic Force Microscope)

Abstract

The invention discloses integrated optical fiber probe type near-field optical tweezers and a method for measuring near-field optical trapping force by an AFM (Atomic Force Microscope). The AFM is used for measuring relation curves between acting forces and probe-base distances before and after light transmission, and the method is used for detecting the near field optical trapping force according to the two forces-distance curves. In a process that the AFM probe approaches and leaves a base surface to acquire the force-distance curves, by means of adding a near-field optical field outside the optical fiber probe type near-field optical tweezers, the AFM probe is exposed to the action of the optical trapping force in the process of converting an evanescent field into a homogeneous field. By the comparison of the force-distance curves before and after light transmission, the near-field optical trapping force can be calibrated for the optical fiber probe type near-field optical tweezers. According to the invention, the difficulty of a fluid mechanics detection method is overcome, and a method for measuring the optical trapping force distribution of laser near-field optical tweezers is provided.

Description

Technical field [0001] The invention relates to the fields of near-field optics and nano-operations, in particular to a method for measuring near-field optical trap force by integrating optical fiber probe type near-field optical tweezers and AFM. Background technique [0002] Utilizing the force of the cow's order generated by the mechanical effect of light, the far-field optical tweezers can achieve precise positioning and manipulation of tiny particles (submicron to tens of microns in size) at the laser focal point, but due to the optical diffraction limit Its capture size is only limited to the order of microns. In addition, due to the lengthening of the focal spot size, the capture of excess particles will occur near the optical potential well, so its capture accuracy and stability will also be affected. Since the basic principle of the optical operation method lies in the effect of the light trapping force on the object, the optical operation of the particles is not limited...

AI Technical Summary

Problems solved by technology

Through the recording of the particle operation process, the obtained particle moving image sequence contains the position information at the corresponding time. After the image is processed, the position change of the edge of the particle image can be directly compared to obtain the particle displacement information at the corresponding time. However, the current image processing It is difficult for technology to effectively suppress the influence of clutter signals and non-target signals in the nanometer range, so it is difficult to achieve high-precision displacement measurement

It can be seen that since the optical trapping force and particle capture size of the fiber-optic probe-type near-field optical tweezers are much smaller than the corresponding size of the far-field optical tweezers, the measurement of the optical trapping force requires higher system sensitivity and observation accuracy, so it is difficult to use Measurement and Calibration of Near-field Optical Trap Force by Fluid Mechanics Method

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