Kyongsik Choi

Full parallax viewing-angle enhanced computer-generated holographic 3D display system using integral lens array

A novel full parallax and viewing-angle enhanced computer-generated holographic (CGH) three-dimensional (3D) display system is proposed and implemented by combining an integral lens array and colorized synthetic phase holograms displayed on a phase-type spatial light modulator. For analyzing the viewing-angle limitations of our CGH 3D display system, we provide some theoretical background and introduce a simple ray-tracing method for 3D image reconstruction. From our method we can get continuously varying full parallax 3D images with the viewing angle about +/-6 degrees . To design the colorized phase holograms, we used a modified iterative Fourier transform algorithm and we could obtain a high diffraction efficiency (~92.5%) and a large signal-to-noise ratio (~11dB) from our simulation results. Finally we show some experimental results that verify our concept and demonstrate the full parallax viewing-angle enhanced color CGH display system.

Full-color autostereoscopic 3D display system using color-dispersion-compensated synthetic phase holograms

A novel full-color autostereoscopic three-dimensional (3D) display system has been developed using color-dispersion-compensated (CDC) synthetic phase holograms (SPHs) on a phase-type spatial light modulator. To design the CDC phase holograms, we used a modified iterative Fourier transform algorithm with scaling constants and phase quantization level constraints. We obtained a high diffraction efficiency (~90.04%), a large signal-to-noise ratio (~9.57dB), and a low reconstruction error (~0.0011) from our simulation results. Each optimized phase hologram was synthesized with each CDC directional hologram for red, green, and blue wavelengths for full-color autostereoscopic 3D display. The CDC SPHs were composed and modulated by only one phase-type spatial light modulator. We have demonstrated experimentally that the designed CDC SPHs are able to generate full-color autostereoscopic 3D images and video frames very well, without any use of glasses.

Analytic design and visualization of multiple surface plasmon resonance excitation using angular spectrum decomposition for a Gaussian input beam

We propose an exact design, analysis, and visualization method for multiple surface plasmon resonance (MSPR) mode excitation phenomena for a structure composed of an optimized-thickness polymethyl-methacrylate layer and a gold thin-film layer. The proposed simulation method is based on a recursive transfer matrix method (R-TMM) and Gaussian angular spectrum decomposition. Our method illustrates, under the Kretchmann-Raether attenuated total reflection (ATR) geometry, the response for an angle-modulated Gaussian incident beam. To verify the simulation results we also performed experiments to excite MSPR modes under the ATR geometry. Our fast and exact R-TMM with the Gaussian angular spectrum method can be widely applied to the design and analysis of metal- and dielectric-composed thin film structures.

Synthetic phase holograms for auto-stereoscopic image displays using a modified IFTA

A Fourier-transformed synthetic phase hologram for an auto-stereoscopic image display system is proposed and implemented. The system uses a phase-only spatial light modulator and a simple projection lens module. A modified iterative Fresnel transform algorithm method, for the reconstruction of gray-level quantized stereo images with fast convergence, high diffraction efficiency and large signal-to-noise ratio is also described. Using this method, it is possible to obtain a high diffraction efficiency(~90%), an excellent signal-to-noise ratio(> 9.6dB), and a short calculation time(~3min). Experimentally, the proposed auto-stereoscopic display system was able to generate stereoscopic 3D images very well.

Real-time digital holographic beam-shaping system with a genetic feedback tuning loop

A novel implementation of a real-time digital holographic system with a genetic feedback tuning loop is proposed. The proposed genetic feedback tuning loop is effective in encoding optimal phase holograms on a liquid-crystal spatial light modulator in the system. Optimal calibration of the liquid-crystal spatial light modulator can be achieved via the genetic feedback tuning loop, and the optimal phase hologram can then overcome the aberration of the internal optics of the system.

Characterization of a subwavelength-scale 3D void structure using the FDTD-based confocal laser scanning microscopic image mapping technique

In this paper, a simple confocal laser scanning microscopic (CLSM) image mapping technique based on the finite-difference time domain (FDTD) calculation has been proposed and evaluated for characterization of a subwavelength-scale three-dimensional (3D) void structure fabricated inside polymer matrix. The FDTD simulation method adopts a focused Gaussian beam incident wave, Berengers perfectly matched layer absorbing boundary condition, and the angular spectrum analysis method. Through the well matched simulation and experimental results of the xz-scanned 3D void structure, we first characterize the exact position and the topological shape factor of the subwavelength-scale void structure, which was fabricated by a tightly focused ultrashort pulse laser. The proposed CLSM image mapping technique based on the FDTD can be widely applied from the 3D near-field microscopic imaging, optical trapping, and evanescent wave phenomenon to the state-of-the-art bio- and nanophotonics.

Diffractive Optic Synthesis and Analysis of Light Fields and Recent Applications

The synthesis and analysis of light fields having specific properties are the main issues in diffractive optics. Light field synthesis technology with diffractive optical elements can provide actual solutions for various applications that require extraordinary optical functions. Also, the rigorous analysis of a light field is an essential element for the design and application of micro- or nanoscale diffractive optical elements. In this paper we review the theoretical aspects of the diffractive optic synthesis and analysis of light fields, and present some recent applications of diffractive optical elements for information, nano-, and biotechnologies.

Geometrical analysis of optical transmission characteristics of prism sheet layers

We analyze the optical transmission characteristics of prism sheet layers based on a geometrical approach. An analytic method for finding the radiant intensity profile of the light transmitted through a single prism sheet for an incident light with arbitrary radiant intensity profile is developed. It is shown that the output radiant intensity profile is the inner product of the newly defined partial transmission coefficient distribution of the prism sheet and the input radiant intensity profile. The developed analysis method for a single prism sheet is immediately generalized to analyze prism sheet layer being composed of several prism sheets.

A single-stage reconfigurable 2-D optical perfect-shuffle network system using multiplexed phase holograms

We propose a single-stage reconfigurable two-dimensional (2-D) optical perfect-shuffle network system (PSNS) using multiplexed phase holograms on one phase-type spatial light modulator (SLM). Phase holograms are used that adopt dynamically combined and multiplexed holograms to implement 2-D perfect shuffling of optical images. Experimentally, we demonstrate the proof-of-principle of the proposed single-stage reconfigurable 2-D optical PSNS using a collimated light source, the multiplexed phase holograms on a phase-type SLM, and a Fourier transform lens.

Applications of holographic devices for optical communications

In this paper, the applications of holographic devices for optical communications are reviewed and discussed. In dense wavelength division multiplexing (DWDM) optical communication systems, holographic devices have some potential applications to satisfy the complex requirements of the systems. We explain recent accomplishment in this field using holographic gratings (HGs) recorded in a photorefractive crystal or a photopolymer. General properties of the HG as a filter are reviewed. We note that the photopolymer HG can be used as a wavelength demultiplexer in DWDM system. It uses spatial dispersion properties of diffraction grating, which provides wavelength-dependent diffraction angle change to separate the multiplexed wavelength channels. The HG device has inherent advantages compared to the other device technologies. As specific applications of the device, we propose chromatic dispersion management of the multiple channel wavelength demultiplexer, channel wavelength tuning of the device output, and double band demultiplexer using superposed HGs. Also, we discuss optical signal routing using computer-generated holograms (CGHs) on a phase spatial light modulator. We expect that these HG devices and CGH system can exploit phase control, tunability, multiplexing and dynamic imaging control of holograms to cope with various DWDM system requirements.