Structure and detection method of a fiber point diffraction interferometer

Abstract

The invention discloses a structure of an optical fiber point diffraction interferometer and a detection method thereof. The structure at least includes a laser, a beam splitter, a measuring optical coupling lens, a reference optical coupling lens, a measuring optical fiber, a reference optical fiber, a measured element and its Adjustment mechanism, charge-coupled device imaging system and image analysis computer; the light emitted by the laser is incident on the beam splitter, and the light is divided into two beams, one beam is coupled to the measurement optical fiber through the measurement optical coupling lens, and the other beam is coupled to the measurement fiber through the measurement optical coupling lens. The reference optical coupling lens is coupled to the reference optical fiber, the two beams of light overlap and interfere, and interference fringes are generated on the imaging surface of the charge-coupled device imaging system, and the image analysis computer is used to analyze the interference fringes to obtain the surface shape of the measured surface of the measured component situation. The invention utilizes two optical fiber cores to diffract to generate standard circular spherical waves as ideal spherical wave light sources, which are respectively used as reference spherical waves and measurement spherical waves. The optical fiber of the invention is easy to manufacture and has low cost.

Description

technical field [0001] The invention relates to a technology and device for optical surface shape detection, especially point diffraction interference technology and interferometer using optical fiber to generate standard spherical waves, which are used in the fields of high-precision optical element surface shape detection and optical system wave front detection. Background technique [0002] With the continuous development of optical technology and technology, the precision requirements for optical components are getting higher and higher, and even the optical diffraction limit resolution is required. The processing accuracy of optical components is mainly limited by the accuracy of the interference standard mirror itself in interferometric technology. The interference standard mirror of the high-precision interferometer is difficult to process and assemble, and the cost is very high. The technique of generating standard spherical waves using point diffraction (US Patent ...

AI Technical Summary

Problems solved by technology

[0006] 1. Since it is difficult to make an ideal circular mask hole by etching and other methods, the light wave diffracted by the hole may cause the spherical wave to be less than ideal

[0007] 2. The spherical wave generated by a small hole in a mask plate itself has little energy because the small hole is too small, and it must be divided into two parts: the reference wave surface and the measurement wave surface. When detecting a circular surface, it is equivalent to cutting out a wave in a large circle. Two small circles will cause a lot of energy waste and affect the generation of interference images

[0008] 3. Because the spatial positions of the standard spherical wave diffracted by the small hole and the measured spherical wave are very close, and interference imaging must also be considered, the overall structure is limited by space, and it is inconvenient to adjust and operate during detection

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