Three-wavelength digital holography detection device and method based on transmission point diffraction

Abstract

The invention provides a three-wavelength digital holography detection device and method based on transmission point diffraction. Incident light of three wavelengths converged in one beam forms reference light and object light of focusing. After the reference light is irradiated to a hole array and is filtered by a pinhole A, the light is divided into reference light of three wavelengths through a second lens and a second color combination prism, the reference light is irradiated to three plane mirrors and reflected, then the reference light passes through the second color combination prism, the second lens, three large holes B of the hole array and a non-polarizing beam-splitting prism to be irradiated to a fourth lens. The object light passes a third lens to be irradiated to the plane mirrors and then is reflected, and the object light passes through the third lens and the non-polarizing beam-splitting prism to be irradiated to the fourth lens. The reference light and the object light converged at the fourth lens generate interference to form a hologram for three-frequency multiplexing, and the hologram is collected by an image sensor and is uploaded to a computer to calculate a phase to be detected. The device has the advantages of a simple structure and good stability, and the hologram can be recorded only with a black and white image sensor.

Description

technical field [0001] The invention belongs to the field of digital holographic detection, in particular to a three-wavelength digital holographic detection device and method based on transmission point diffraction. Background technique [0002] Due to its unique advantages such as non-contact, full-field quantification, and three-dimensional imaging, digital holographic detection technology has been widely used in the measurement fields of biomedicine, micro-nano devices, and optical micro-machining as an extremely important test and analysis method. However, due to the distribution of sine and cosine functions of hologram fringes, the phases obtained by traditional single-wavelength digital holography are mostly wrapped phases, which require complex and time-consuming algorithms to realize phase unwrapping. Three-wavelength digital holography uses three beams of illumination light to synthesize an equivalent wavelength larger than the thickness of the sample to be measure...

AI Technical Summary

Problems solved by technology

[0003] Patent CN106569402A "A Color Separation and Digital Processing Method for Multi-Wavelength Digital Holograms" first uses a Bayer-type color camera to separately collect single-wavelength digital holograms of objects under three-color laser irradiation, and obtains the crosstalk coefficient between the three colors through numerical processing Matrix; then collect multi-wavelength digital holograms irradiated by three-color lasers at the same time, and use the crosstalk coefficient matrix to eliminate the crosstalk between the three channels caused by the incomplete selectivity of Bayer color filters to different wavelengths of light, realizing a single digital hologram holographic Figure 1 Record information of multiple wavelengths at one time, but this method not only has high cost, low resolution, but also complicated operation, which cannot realize online real-time detection

[0004] Patent CN101452253B "A Method for Acquiring Color Digital Holograms" utilizes black-and-white area array CCD and multi-recording wavelength lensless Fourier transform hologram recording optical path to realize three-wavelength digital holographic imaging, but this method still needs to record each wavelength separately Hologram, and requires complex algorithms to reproduce imaging, poor real-time performance, and because of the use of separate optical paths, poor anti-interference ability

[0005] Patent CN105717774A "A device and method for real-time recording of color digital holograms" under the condition that the illumination angles of the object beams are consistent, the irradiation angles of the reference beams are adjusted respectively, and holograms containing different carrier frequencies of each wavelength are obtained through one exposure to realize dynamic Real-time holographic recording of colored objects, but the light beams of each wavelength of the device pass through different positions in space, which not only results in a large and complex structure, difficult adjustment, but also poor anti-interference ability

[0006] French SONG Qinghe et al. (Song Q, Wu Y, Tankam P, et al.Research on therecording hologram with Foveon in digital color holography[C] / / PhotonicsAsia.International Society for Optics and Photonics,2010) use color camera to record hologram, The light beams of each wavelength can share one optical path, which greatly simplifies the system structure and reduces the complexity of system operation. However, because of the use of color cameras, not only the cost is high, but also complex algorithms are required to suppress the crosstalk between each wavelength; at the same time, because Using separate optical path, poor anti-interference ability

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