Device and method for measuring nanometer displacement based on phase modulation with dual laser single-frequency interference
A phase modulation and displacement measurement technology, applied in the field of precision measurement, can solve problems such as limiting measurement accuracy, and achieve the effect of simple optical path structure, convenient use, and avoiding sinusoidal errors or non-orthogonal errors.
Active Publication Date: 2019-02-15
ZHEJIANG SCI-TECH UNIV
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Heterodyne interferometer is a kind of AC interferometer, which can overcome the influence of DC light intensity drift, but due to the first-order nonlinear error caused by frequency aliasing and polarization aliasing, the improvement of measurement accuracy is limited.
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[0027] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.
[0028] Such as figure 1 As shown, the present invention includes a single-frequency laser 1, a first beam splitter 2, a second beam splitter 3, a third beam splitter 4, a fourth beam splitter 5, an electro-optical phase modulator 6, a high-voltage amplifier 7, a signal generator 8, Reference corner cube prism 9, measuring corner cube prism 10, first photodetector 11 and second photodetector 12; Single-frequency laser 1 output wavelength is that the linearly polarized light of λ is directed to the first beam splitter 2, and the first beam splitter 2. The transmitted light beam is sent to the second beam splitter 3, and the reflected beam of the second beam splitter 3 is modulated by the electro-optical phase modulator 6 and then directed to the reference corner cube 9, and the light beam reflected by the reference corner cube 9 is sent to the fourth be...
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The invention discloses a phase modulation based dual-laser single-frequency interference nanometer displacement measurement device and method. The device is characterized in that a single-frequency laser outputs single-wavelength linear polarized light, the single-wavelength linear polarized light shoots to a dual-laser single-frequency interferometer formed by four spectroscopes and two pyramid prisms, measurement interference signals and reference interference signals are formed respectively, and the measurement interference signals and the reference interference signals are received by two photoelectric detectors respectively; an electro-optic phase modulator is placed in a light path, periodic sawtooth voltage signals are applied to the electro-optic phase modulator, and the measurement and reference DC interference signals are modulated into AC interference signals; and the variation in phase difference, which is caused by movement of a measured object, of the two path of interference signals is detected so as to acquire the measured displacement. The device disclosed by the invention overcomes an error introduced by DC drift of the single-frequency interferometer, avoids a sine error or a non-orthogonal error brought about by direct subdivision for the measurement interference signals, has sub-nanometer-scale measurement precision, and is applicable to precision displacement measurement in the field of high-end equipment manufacturing and processing.
Description
technical field [0001] The invention relates to a single-frequency interference displacement measurement method and device, in particular to a dual-laser single-frequency interference nano-displacement measurement device and method based on phase modulation, which belongs to the technical field of precision measurement. Background technique [0002] High-precision nano-displacement measurement has important applications in technical fields such as ultra-precision machining, microelectronics manufacturing, and precision testing and measurement. Laser interferometry technology is widely used in nanometer displacement measurement because of its advantages of large measurement range, high resolution and meter traceability. According to the measurement principle, laser interferometry is mainly divided into two categories: single-frequency interferometer and heterodyne interferometer. The laser single-frequency interferometer is a kind of DC interferometer. The drift of DC light ...
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IPC IPC(8): G01B11/02
CPCG01B11/02
Inventor 严利平陈本永
Owner ZHEJIANG SCI-TECH UNIV