Holography|2 Article(s)
Digital holographic microscopy with phase-shift-free structured illumination
Juanjuan Zheng, Peng Gao, Baoli Yao, Tong Ye, Ming Lei, Junwei Min, Dan Dan, Yanlong Yang, and and Shaohui Yan
When structured illumination is used in digital holographic microscopy (DHM), each direction of the illumination fringe is required to be shifted at least three times to perform the phase-shifting reconstruction. In this paper, we propose a scheme for spatial resolution enhancement of DHM by using the structured illumination but without phase shifting. The structured illuminations of different directions, which are generated by a spatial light modulator, illuminate the sample sequentially in the object plane. The formed object waves interfere with a reference wave in an off-axis configuration, and a CCD camera records the generated hologram. After the object waves are reconstructed numerically, a synthetic aperture is performed by an iterative algorithm to enhance the spatial resolution. The resolution improvement of the proposed method is proved and demonstrated by both simulation and experiment.
Photonics Research
  • Publication Date: May. 15, 2014
  • Vol. 2, Issue 3, 03000087 (2014)
Review of fast methods for point-based computer-generated holography [Invited]
P. W. M. Tsang, T.-C. Poon, and Y. M. Wu
Computer-generated holography (CGH) is a technique for converting a three-dimensional (3D) object scene into a two-dimensional (2D), complex-valued hologram. One of the major bottlenecks of CGH is the intensive computation that is involved in the hologram generation process. To overcome this problem, numerous research works have been conducted with the aim of reducing arithmetic operations involved in CGH. In this paper, we shall review a number of fast CGH methods that have been developed in the past decade. These methods, which are commonly referred to as point-based CGH, are applied to compute digital Fresnel holograms for an object space that is represented in a point cloud model. While each method has its own strength and weakness, trading off conflicting issues, such as computation efficiency and memory requirement, they also exhibit potential grounds of synergy. We hope that this paper will bring out the essence of each method and provide some insight on how different methods may crossover into better ones.
Photonics Research
  • Publication Date: Aug. 07, 2018
  • Vol. 6, Issue 9, 09000837 (2018)