Holography

  • High levels of color uniformity and optical efficiency for a wedge-shape waveguide-type wearable display using photopolymer


  • The structure of wedge-shaped waveguide-type wearable display


    Schematic illustration of the multicolor reflection volume holographic grating recording setup for HMD


    Experimental results

  • Holographic microscope with improved phase contrast using SLM


  • Experimental setup for recording hologram


    Holographic recording: a) original phase contrast microscopy, b) with 4-phase fringes, c) 6-phase fringes and d) 8-phase fringes

  • Improving processing speed and resolution for the CGH generation


  • Double wavefront recording plane are used to enhance the speed of the digital hologram generation with the pre-project 3D object to 2 grids of intensity and depth

  • Optical image split-encryption based on object plane for completely removing the Silhouette problem

  •      Ø Split-encryption scheme on converting original images to multiple ciphertexts.
         Ø Original image is mathematically split into two POFs and modulated on a SLM one after another.
         Ø Subsequently two final ciphertexts are generated by utilizing two-step phase-shifting interferometry.
         Ø High-quality reconstructed image with relative error RE = 7.6061×10-31 can be achieved.


    Schematic configuration that shows how to realize the Fresnel transform of one single phase-only function by two-step phase-shifting method

  • Fast calculation for CGCH using wavefront recording surface

  •      Ø Virtual wave-front recording surface (WRS) was placed between the object and CGCH.
         Ø The optical field from object to the CGCH surface was calculated on the virtual surface first, and the optical field in WRS was then Fresnel transformed to the CGCH plane by the Fast Fourier Transform (FFT).
         Ø As the WRS was close to the object, so the active area of one object point was small.



    The scheme of WRS method Hologram of two point sources

  • CGH for orthoscopic-converted surface model


  • Schematic configuration of the CGH display for the surface model


    CGH generation for the polygon-based surface model

  • Fabrication of solar concentrator using HOE and Fresnel lens

  •      Ø Record the property of Fresnel lens is photopolymer used as solar concentrator.
         Ø Study the angular selectivity for sun tracking system.
         Ø Optimize the greatest diffraction efficiency condition.
         Ø High concentration rate & overcome the heat problem.


    Experimental setup and results