Erkhembaatar Dashdavaa

We reduced image noise in broadband full‐color holographic image capture in a compact self‐interference incoherent digital holography (SIDH) system by combining a cholesteric liquid crystal (CLC) circular polarizer with a quarter‐waveplate‐based geometric phase lens (QW‐GPL). To address chromatic wavefront noise issues commonly found in conventional half‐waveplate‐based SIDH systems, we explore a SIDH system incorporating a quarter‐waveplate‐based GPL (QW‐GPL). In particular, we resolve angular polarization‐dependent noise in QW‐GPL wavefront modulation by utilizing circularly polarized Bragg reflection of CLC as a circular polarization filter. This approach ensures an ideal circularly polarized beam state across a wide range of incident angles and wavelengths. By effectively mitigating circular polarization distortion in QW‐GPL, our method significantly improves the quality of reconstructed holographic images in full‐color SIDH with a compact form factor, as demonstrated by reduced entropy values.

We propose generated a high-quality 3D model using a deep neural network by acquiring high-resolution 3D data from real-world objects and generated a high-speed and high-quality 3D CGH based on integrated hybrid map layering for use in holographic display.

With the development of the holographic printer, printing synthetic hologram requires smaller holographic element (hogel) size to improve spatial resolution of the reconstruction. On the contrary, a larger hogel size affords higher angular resolution, but it leads to a lower lateral resolution and there exists a trade-off problem. In this paper, a hologram synthesis method based on three-dimensional (3D) rendering of computer-generated holographic stereogram (HS) is proposed to limit the spatial-angular trade-off problem. The perspectives of the 3D scene are captured by re-centering the camera method and transformed into parallax-related images by a proposed pixel re-arrangement algorithm for holographic printing. Unlike the conventional approaches, the proposed algorithm not only improves the angular resolution of the reconstruction while maintaining the hogel size fixed, but also keeps the spatial resolution without degradation. The effectiveness of the proposed method is verified by numerical simulation and an optical experiment.

A design and implementation of full-parallax holographic stereogram printer is presented. The holographic stereogram is synthesized using 2D perspective images of the 3D object that are rendered from multiple directions. The perspective images of the 3D scene are firstly captured by a virtual camera and transformed to two-dimensional holographic elements called hogels. The hogels are exposed using the perspective images to form the whole holographic stereogram. After all the hogels are exposed successively, a holographic stereogram can be achieved. Numerical simulation and optical reconstructions are implemented.

In this paper, we present an algorithm for complex object wave extraction in off-axis digital holography using a time-multiplexing and frequency spectrum-shifting technique. The proposed approach utilizes the digital time-multiplexing technique, in which two 90-deg-rotated off-axis holograms are recorded in sequence, and corresponding spectra are subtracted in the computed Fourier domain to eliminate the DC term. Then, the two subtracted holograms are digitally multiplexed into one complex hologram in the same plane, and by shifting the spatial frequency spectra of the subtracted hologram in the spatial frequency domain, one of the two cross-correlations can be obtained in the center. This technique simply extracts the spectrum of the real image in the frequency domain than the spatial filtering method. (C) 2017 Optical Society of America