We propose dual-wavelength digital holographic microscopy with a slightly off-axis configuration. The axial measurement range without phase ambiguity is extended to the micrometer range by synthesizing a beat wavelength between the two wavelengths with separation of 157 nm. Real-time measurement of the specimen is made possible by virtue of the high wavelength selectivity of the Bayer mosaic filtered color CCD camera. The principle of the method is exposed, and the practicability of the proposed configuration is demonstrated by the experimental results on a vortex phase plate and a rectangular phase step.
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http://dx.doi.org/10.1364/ao.51.000191 | DOI Listing |
Traditional numerical reconstruction methods in digital holography (DH) are faced with problems such as inaccurate and time-consuming unwrapping or the need to capture multiple holograms with different diffraction distances. In recent years, deep learning, believed to be a new and effective optimization tool, has been widely used in digital holography. However, most supervised deep learning methods require large-scale paired data, and their preparation is time-consuming and laborious.
View Article and Find Full Text PDFPhase-shifting Fringe projection profilometry (FPP) excels in 3D measurements for many macro-scale applications, but as features-of-interest shrink to the microscopic scale, depth-of-field limitations slow measurements and necessitate mechanical adjustments. To address this, we introduce digital holography (DH) for fringe image capture, enabling numerical refocusing of defocused object regions. Our experiments validate this approach and compare depth measurement noise with other DH and FPP methods.
View Article and Find Full Text PDFGhost holography has attracted notable applied interest in the modern quantitative imaging applications with the futuristic features of complex field recovery in the diversified imaging scenarios. However, the utilization of digital holography in ghost frame works introduces space bandwidth or time bandwidth restrictions in the implementation of the technique in applied domains. Here, we propose and demonstrate a quantitative ghost phase imaging approach with holographic ghost diffraction scheme in combination with the phase-shifting technique.
View Article and Find Full Text PDFHolographic light potentials generated by phase-modulating liquid-crystal spatial light modulators (SLMs) are widely used in quantum technology applications. Accurate calibration of the wavefront and intensity profile of the laser beam at the SLM display is key to the high fidelity of holographic potentials. Here, we present a new calibration technique that is faster than previous methods while maintaining the same level of accuracy.
View Article and Find Full Text PDFDigital micromirror devices (DMDs), owing to their rapid refresh rates and ability to shape particular optical patterns, are key tools for holographic 3D near-eye displays. However, relying on a single-sideband (SSB) filter to eliminate crosstalk from zero-order and conjugate noise leads to an enormous decrease in the utilization of spatial bandwidth product (SBP). In this paper, we develop a new strategy for the binary hologram optimization framework to enable the full utilization of SBP of DMD holographic display by minimizing conjugate noise.
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