Reflection-type off-axis digital holographic microscopy measurement device

Abstract

The invention discloses a reflection-type off-axis digital holographic microscopy measurement device, which comprises a light source unit, an object light adjusting unit, a reference light adjusting unit and an image processing unit. The reference light adjusting unit comprises an optical path adjustment reflector group and an optical path guidance reflector group. The optical path adjustment reflector group comprises a first reflector and a second reflector, the positions of which are relatively fixed. The first reflector is used for reflecting the reference light R to the second reflector; the second reflector is used for reflecting the input reference light R to the optical path guidance reflector group; the optical path of the reference light R can be adjusted by moving the optical path adjustment reflector group wholly; the optical path guidance reflector group can guide the reference light R, the optical path of which is adjusted, to be input to the image processing unit to have interference with reflected light O'; and the image processing unit is used for processing interference fringes to obtain a sample three-dimensional image. The device can improve the quality of the holographic image.

Description

Technical field [0001] The invention belongs to the field of digital holographic microscopic measurement, and more specifically, relates to a reflective off-axis digital holographic microscopic device for real-time measurement of the three-dimensional topography of a non-transparent sample surface. Background technique [0002] Since lasers and digital image sensors (CCD or CMOS) have matured, digital holography technology has been widely used. It realizes the reconstruction of three-dimensional topography through digital image processing techniques such as fast Fourier transform, spectral filtering, and diffraction light field reconstruction on the recorded hologram. The off-axis digital holography technology avoids the scanning process of traditional optical profile measurement, and has the advantages of real-time full-field three-dimensional measurement without precise focusing. [0003] At present, when using digital holography to measure transparent samples, because the sampl...

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Problems solved by technology

(2) Professor Etienne Cuche, Professor Myung K.Kim from the University of South Florida in the United States and others used a modified device similar to the optical path of the Mach-Zehnder interferometer, which ignored the fact that the optical path of the object light is more than the optical path of the reference light. The optical path difference in the hologram is reduced by using a laser with a longer coherence length to compensate for the decrease in the visibility of the interference fringes in the hologram, but the laser with a better coherence also causes the problem of aggravating the laser speckle noise in the hologram (Cuche E, Marquet P, Depeursinge C. Simultaneous amplitude-contrast and quantitative phase-contrast microscopy by numerical reconstruction of Fresnel off-axisholograms[J].Applied optics,1999,38(34):6994-7001 and Kim M K, Yu L, Mann C J. Interference techniques in digital holography[J].Journal of OpticsA:Pure and Applied Optics,2006,8(7):S518.)

(3) In addition to the above two other devices, complex and expensive optical devices also need to be used, which leads to the problems of complex structure and expensive equipment

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