Polarized Miller Interferometry Device and Measurement Method with Adjustable Fringe Contrast

Abstract

The invention relates to a polarization type Miller interference device and a measurement method with adjustable fringe contrast. The polarizing Miller interference device includes a CCD detector, an imaging lens, a polarizer, a quarter wave plate, a beam splitter, a microscope objective lens, a reference mirror, and a nanowire grid polarizer arranged sequentially from top to bottom. The polarized laser, polarizer and collimator beam expander system are arranged on the right side of the beam splitter from right to left. The measurement method is as follows: Rotate the light transmission axis of the analyzer 5 times along the same direction with a 45° rotation step, and obtain 5 phase-shifted interference fringe patterns with a phase difference of 90° on the CCD detector, and then use five The measurement can be realized by stepping the phase shift algorithm; the adjustment of the fringe contrast can be realized by adjusting the direction of the transmission axis of the polarizer. The invention can conveniently adjust the fringe contrast, effectively solve the problem of inconsistent phase-shifting interference fringe contrast caused by the low extinction ratio of the reflected light of the nanowire grid polarizer, and satisfy the high-precision measurement of samples to be tested with low reflectivity.

Description

technical field [0001] The invention belongs to the technical field of optical measurement, and in particular relates to a polarization-type Miller interference device and a measurement method with adjustable fringe contrast. Background technique [0002] With the development of modern precision measurement technology, Miller interferometer has been widely used in the field of optical detection and metrology due to its compact structure, high measurement accuracy and high spatial resolution, such as non-contact measurement of biomedicine, optical profile and size structure. . The basic principle of the Miller interferometer is consistent with that of the Michelson interferometer. The difference between the two lies in the physical location of the reference arm. in the Miller objective. Due to the fixed relative light intensity ratio between the measuring arm and the reference arm of the traditional Miller interferometer, the contrast of the interference fringe cannot be ad...

AI Technical Summary

Problems solved by technology

[0003] The present invention mainly solves the technical problems that the original polarization-type Miller interference system generally has a complex structure, requires the use of complex special polarization devices, high manufacturing costs, difficult adjustment, inconvenient measurement, and low measurement accuracy; it provides a fringe The polarization-type Miller interferometry device and measurement method with adjustable contrast have a simple structure, reduce costs, facilitate adjustment, facilitate measurement, and improve measurement accuracy, especially for high-precision measurement of samples with low reflectivity to be measured

[0004] Another object of the present invention is to provide a polarization-type Miller interference device and measurement method with adjustable fringe contrast, which can effectively solve the problem of inconsistency in phase-shifting interference fringe contrast caused by the low extinction ratio of reflected light of the nanowire grid polarizer, and is easy to operate. Improve the measurement accuracy and meet the high-precision measurement of samples with low reflectivity

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