A Displacement Sensing Method Based on Combined Calculation of Multi-order Axial Modes in Whispering Gallery Microcavity

Abstract

The invention discloses a displacement sensing method based on multi-order axial mode joint solution of an echo wall micro cavity. The method comprises acquisition of a multi-order axial mode and construction of a sensing model. Acquisition of the multi-order axial mode is achieved through a micro cavity coupling system, laser emitted by a tuned laser device enters the micro cavity coupling systemthrough a polarization controller, and the resonance spectrum of a micro cavity is obtained through utilizing a photoelectric detector; construction of the sensing model is based on the resonant spectrum of different coupling positions of the micro cavity, a three-dimensional curved surface map of the resonance spectrum is obtained through moving the micro cavity, position coding and calibrationare performed for the map, in combination with the precise positioning method in the coding section, large-range and high-resolution displacement sensing in the axial direction of the micro cavity isachieved. The method is advantaged in that influence of environmental factors such as external temperature change on sensing accuracy can be effectively reduced, moreover, the shortcoming that the wide range and high resolution can not be both achieved in a single-mode sensing scheme is overcome.

Description

technical field [0001] The invention belongs to the technical field of optical sensing, and more specifically relates to a displacement sensing method based on joint calculation of multi-order axial modes of a whispering gallery microcavity. Background technique [0002] Whispering gallery microcavity, as a high-performance optical microresonator cavity, has attracted widespread attention and applications due to its extremely high Q value characteristics, and has shown excellent performance in many high-sensitivity sensing fields such as micro-displacement measurement, micro-force measurement, and biochemical sensing. performance. Experiments and theory show that for a Q value of 10 7 The whispering gallery microcavity, if it is used for displacement sensing, the theoretical resolution can reach sub-nanometer level. [0003] In recent years, the research on displacement sensing based on whispering gallery microcavity has become more and more extensive. According to differe...

AI Technical Summary

Problems solved by technology

The first scheme is mainly to convert the displacement into the deformation of the microcavity, and realize the displacement detection by constructing the relationship between the deformation and the resonant peak shift. Since the central wavelength of the resonant peak is extremely sensitive to the external temperature, this scheme is difficult to achieve high Accuracy measurement

The second scheme is mainly to convert the displacement into the change of coupling conditions, and then change the Q value and transmittance of the resonant mode in the cavity, and realize displacement sensing based on the Q value or transmittance. This scheme is not sensitive to temperature, but is limited to the mode Field distribution characteristics, the traditional displacement sensing scheme based on a single mode is difficult to achieve both large range and high resolution

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