Dual wavelength common-channel quadrature carrier frequency digital holographic detection apparatus and detection method

Abstract

The invention provides a dual wavelength common-channel quadrature carrier frequency digital holographic detection apparatus and a detection method. A non-polarization splitting prism splits converged dual wavelength incident light into reflected reference light and transmitted object light; the reference light irradiates an aperture reflector and is reflected; the object light is split into dual wavelength object lights when passing through a dichroscope; the dual wavelength object lights separately irradiate a first reflector and a second reflector and are reflected and passes through the dichroscope to merge into a beam of object light; The reflected reference light and object light are combined by a non-polarization splitting prism into a beam of light which passes through a second lens to form a quadrature carrier frequency hologram which is collected by a computer via an image sensor and the phase of the object to be measured is calculated. The detection method ensures the anti-interference ability and wrap-free real-time detection; and the method is simple and is easily implemented without need of any optical members such as polarization elements and space filter arrays, and only the hologram recorded by a black-white image sensor and completion of the dual-wavelength hologram separation by a simple algorithm are needed.

Description

technical field [0001] The invention relates to a digital holographic detection device and a detection method, in particular to a dual-wavelength co-channel orthogonal carrier frequency digital holographic detection device and method. Background technique [0002] Based on the principle of interference, digital holographic detection technology uses image sensors such as CCD or CMOS to record holographic (interferometric) images, and uses computers to digitally reproduce the surface topography of objects. The extremely important test and analysis methods are widely used in measurement fields such as biomedicine, micro-nano devices, and optical micro-processing. However, due to the distribution properties of the sine and cosine functions of the interference fringes, the phase distribution of the object reproduced by the arctangent function is a wrapped phase distributed between [-π, π]. When the actual phase jump of the object to be measured exceeds 2π, aliasing will occur, a...

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Problems solved by technology

However, the device needs to use multiple polarizing elements, and because of the separate optical path structure, the anti-interference ability needs to be further improved

[0005] Korean D.Y.Kim et al. (MohammadRezaJafarfard, SucbeiMoon, BehnamTayebi, and DugYoungKim.Dual-wavelengthdiffractionphasemicroscopyforsimultaneousmeasurementofractiveindexandthickness.OpticsLetters.2014,39(10):2908-2911) proposed a dual-wavelength co-path off-axis point diffraction holographic optical system in 4 f Place a grating on the surface, divide the diffraction of the dual-wavelength light wave to be measured into multiple diffraction orders, and place a spatial pinhole filter array on the spectrum plane, select the zero-order light as the reference light and select the +1 order and +2 order as the object light respectively , and then collect color holograms containing different carriers through one exposure. This technology has strong anti-interference ability because of the common path structure, but it has higher requirements for the spatial pinhole filter array, and because of the different diffraction orders, the obtained wavelengths The contrast of holograms is quite different, requiring complex algorithms for normalization

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