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CN-121804417-B - Heterodyne shearing interference dynamic angle measuring method and device

CN121804417BCN 121804417 BCN121804417 BCN 121804417BCN-121804417-B

Abstract

The application discloses a heterodyne shearing interference dynamic angle measuring method and a heterodyne shearing interference dynamic angle measuring device, and belongs to the technical field of optical angle measurement. The method comprises the steps of providing dual-frequency light beams with different frequencies and orthogonal polarization states, transmitting the dual-frequency light beams to an object to be detected along a quasi-common light path, receiving the emergent light beams deflected by the object to be detected, keeping the quasi-common light path to transmit, separating the emergent light beams into two shearing light beams with orthogonal polarization states to form an interference light path with transverse shearing quantity, heterodyning the shearing light beams, receiving and outputting difference frequency interference electric signals by a photoelectric detector, and finally calculating to obtain the dynamic deflection angle of the object to be detected by demodulating the phase change of the difference frequency signals. The application combines quasi-common light path design and shearing interference, realizes natural decoupling of displacement and rotation in a physical layer, and has high precision, high dynamic response, strong anti-interference capability and good engineering practicability.

Inventors

  • LI WENHAO
  • YU XIANBAO
  • ZHOU WENYUAN
  • LIU ZHAOWU
  • SUN YUJIA
  • CUI YUHANG

Assignees

  • 中国科学院长春光学精密机械与物理研究所

Dates

Publication Date
20260505
Application Date
20260310

Claims (10)

  1. 1. The heterodyne shearing interference dynamic angle measuring method is characterized by comprising the following steps of: Measuring an object to be measured by heterodyning the laser beam; acquiring an emergent light beam carrying the angle change information of the object to be detected; maintaining the quasi-common optical path propagation of the emergent beam, and shearing the emergent beam to separate the emergent beam into shearing beams with relative shearing relation; Acquiring an optical path difference corresponding to the propagation direction of the light beam formed by the shearing light beam in the propagation process, wherein the optical path difference is not changed along with the displacement change of the object to be detected; heterodyne interference is carried out on the shearing light beams, and a difference frequency interference signal is obtained; And determining the dynamic angle of the object to be detected according to the phase change of the difference frequency interference signal.
  2. 2. The method of claim 1, wherein the heterodyne laser beam is a dual frequency beam, and a quasi-common path state is maintained during propagation until the heterodyne laser beam is split into the sheared beam, such that the sheared beam has the same equivalent point of incidence at the object.
  3. 3. The method of measuring according to claim 2, wherein the heterodyne laser beam is a beam of two beams of different frequencies and orthogonal polarization states.
  4. 4. The method of claim 1, wherein the shearing process separates light components of different polarization states in the outgoing light beam to form a sheared light beam having parallel propagation directions.
  5. 5. The method according to claim 1, wherein the phase change between the sheared beams is obtained by beat-demodulating the difference-frequency interference signal.
  6. 6. The method according to claim 5, wherein the dynamic angle is calculated by a preset functional relationship between an interference phase difference and a beam deflection angle.
  7. 7. The method of claim 6, wherein the predetermined functional relationship is determined by an optical path geometry of the sheared beam.
  8. 8. The method of claim 7, wherein the optical path geometry includes an angle between the sheared beams and a propagation distance of the sheared beams on a non-quasi-common optical path.
  9. 9. The measurement method according to claim 8, wherein the expression of the dynamic angle is: Wherein, the The method comprises the steps of obtaining a light beam, wherein the light beam represents the deflection angle of an outgoing light beam caused by an object to be measured, lambda represents the wavelength of the light beam, n represents the refractive index of a medium, K represents a constant determined by the structure of a measuring device, nK=L, and L represents the total optical path; Representing a total phase difference of the difference frequency interference signals; Indicating the initial phase of the measurement light.
  10. 10. A measurement device for heterodyne shear interference dynamic angle for implementing a measurement method according to any one of claims 1 to 9, comprising: The heterodyne light source is used for outputting double-frequency light beams with different frequencies and orthogonal polarization states; the measuring module is used for guiding the double-frequency light beam to the object to be measured and receiving an emergent light beam of the object to be measured; the shearing interference module comprises a light splitting element and a first reflecting light path and a second reflecting light path which are led out by the light splitting element; The light splitting element is used for splitting the emergent light beam into a first polarized light beam and a second polarized light beam and is respectively coupled to the first reflection light path and the second reflection light path, the first reflection light path and the second reflection light path are configured to enable the first polarized light beam and the second polarized light beam to form shearing interference, and the optical path difference between the first polarized light beam and the second polarized light beam is related to the deflection angle of the emergent light beam; and the photoelectric detection module is used for receiving heterodyne interference signals formed by the shearing interference and outputting difference frequency interference electric signals.

Description

Heterodyne shearing interference dynamic angle measuring method and device Technical Field The application relates to the technical field of optical angle measurement, in particular to a heterodyne shearing interference dynamic angle measurement method and a heterodyne shearing interference dynamic angle measurement device. Background The application of laser technology has led to the development of the modern precision measurement field. Among them, the laser angle measurement technique has become a core means of angle measurement due to its high precision, high resolution and dynamic continuous measurement capability. The advantage is rooted in the comprehensive characteristics of wide range, high precision and high speed measurement of the optical measurement method, so that the optical measurement method continuously becomes a research hot spot in the field of ultra-precise measurement. The angle parameters can be divided into static angles and dynamic angles according to the motion characteristics of the angle parameters. At present, the static angle measurement technology is highly mature, and the instrument precision generally reaches the sub-angle second level. However, in the front edge fields of aerial remote sensing, laser communication and the like, a measured target is always in a high-speed or continuously variable-speed rotation state, and the conventional static measurement method cannot meet the real-time tracking requirement due to the inherent limitation of insufficient sampling frequency and delayed dynamic response. In recent years, high-precision dynamic goniometry technology has continuously made breakthroughs, and two representative schemes exhibit different technical paths. 2024, laxman Mandal et al proposed an enhanced Michelson interferometer based on right angle prism side reflecting mirrors (Journal of Optics, 2024, 53 (2): 1545-1550.). The key innovation is that two right angle surfaces of the prism are used as reflecting mirrors, and the double measurement sensitivity compared with the traditional architecture is theoretically realized through an optical path difference amplification principle, so that the superiority of the prism in submicron camber measurement is verified through experiments, but the structure of the prism is sensitive to the motion interference of a measured object. To improve dynamic performance, a dual-frequency laser differential dynamic goniometry method was proposed by group Xu Xin of the university of bloom (IEEE Transactions on Industrial Electronics, 2022, 70 (6): 6405-6413.). The method is based on the frequency modulation feedback interference principle, establishes direct mapping of laser frequency difference and angular displacement through double optical frequency phase decoupling, realizes sub-angular second resolution in a large dynamic range (better than +/-5 degrees), and achieves resolution of 0.02 angular second and long-term stability of 0.15 angular second in experiments. However, the scheme relies on complex subsystems such as acousto-optic modulation and frequency locking, so that the optical path structure and the modulation complexity are obviously increased, and engineering challenges are faced in the scenes such as aviation remote sensing which requires millisecond-level response. Therefore, a measurement method and a device for heterodyne interference dynamic angles based on quasi-common optical paths are needed, and the technical problems that in the prior art, measurement stability is poor, principle errors are difficult to thoroughly eliminate, and requirements on use environments are extremely severe are solved. Disclosure of Invention The application aims to provide a heterodyne interference dynamic angle measuring method and device based on a quasi-common optical path, which can solve at least one technical problem. The specific scheme is as follows: according to a specific embodiment of the application, the application provides a heterodyne shearing interference dynamic angle measuring method, which comprises the following steps: Measuring an object to be measured by heterodyning the laser beam; acquiring an emergent light beam carrying the angle change information of the object to be detected; maintaining the quasi-common optical path propagation of the emergent beam, and shearing the emergent beam to separate the emergent beam into shearing beams with relative shearing relation; acquiring an optical path difference corresponding to the light beam propagation direction formed by the shearing interference light beam in the propagation process, wherein the optical path difference is not changed along with the displacement change of the object to be detected; heterodyne interference is carried out on the shearing light beams, and a difference frequency interference signal is obtained; And determining the dynamic angle of the object to be detected according to the phase change of the difference frequency interference signal.