Jinyoung Roh

Holographic head-mounted display with RGB light emitting diode light source

A compact head-mounted holographic three-dimensional display with an RGB light-emitting diode (LED) light source is developed. Issues regarding full-color holographic image design and the quality associated with the use of an LED light source are investigated. The accommodation effect and background noise in the proposed system are discussed based on experimental observation.

Anamorphic optical transformation of an amplitude spatial light modulator to a complex spatial light modulator with square pixels [Invited]

A method is proposed for the construction of a square pixel complex spatial light modulator (SLM) from a commercial oblong full-high-definition (full-HD) amplitude SLM using an anamorphic optical filter. In the proposed scheme, one half-band of the optical Fourier transform of the amplitude-only spatial light field is rejected in the optical Fourier plane and the other half-band is reformatted to be an effective complex SLM with square pixels. This has an advantage in the viewing window plane since the shape of the viewing window becomes square and more ideal for observers who watch the hologram contents through it. For optimal transformation, the amplitude computer generated hologram encoding scheme was developed. Mathematical modeling of the proposed system is described herein, and it was experimentally demonstrated that the effective complex SLM displays complex holographic three-dimensional images with a clear depth discrimination effect.

Modulation efficiency of double-phase hologram complex light modulation macro-pixels

The modulation efficiency of the double-phase hologram macro-pixel that is designed for complex modulation of light waves is defined and analyzed. The scale-down of the double-phase hologram macro-pixel associated with the construction of complex spatial light modulators is discussed.

Full-color holographic projection display system featuring an achromatic Fourier filter

We propose a full-color complex holographic display system design comprised of three R/G/B amplitude-only spatial light modulators and an achromatic Fourier filter. A key feature of the design is a single achromatic Fourier bandpass filter for robust axial R/G/B color matching, whereby the R/G/B holographic image light fields can be three-dimensionally aligned. The synthesis algorithm producing the full-color computer-generated holograms for this system is described and a full-color optical reconstruction of the designed holographic three-dimensional images is experimentally demonstrated.

Iridescent Specular Structural Colors of Two-Dimensional Periodic Diffraction Gratings

Specular structural colors generated by two-dimensional periodic binary gratings are investigated theoretically. An approximate mathematical model of the grating specular structural colors is described, based on scalar nonparaxial diffraction theory, and the functional relationships of specular structural color and structural parameters of gratings are analyzed. Through this, the optimal condition for maximizing the color-representation range in the standard CIE 1931 chromaticity diagram is derived.

Characteristics of complex light modulation through an amplitude-phase double-layer spatial light modulator

The complex modulation characteristics of a light field through an amplitude-phase double-layer spatial light modulator are analyzed based on the wave-optic numerical model, and the structural conditions for the optimal double-layer complex modulation structure are investigated. The relationships of interlayer distance, pixel size, and complex light modulation performance are analyzed. The main finding of this study is that the optimal interlayer distance for the double-layer structure can be found at the Talbot effect condition. For validating the practical usefulness of our findings, a high quality reconstruction of the complex computer-generated holograms and the robustness of the angular tolerance of the complex modulation at the Talbot interlayer distance are numerically demonstrated.

Numerical visualization of aperiodic scalar optical wave fields

In numerical wave optic simulations using the conventional angular spectrum method, numerical inter-periodic interference occurs as a result of the inherent periodicity of the discrete Fourier transform. In this paper, we propose an aperiodic angular spectrum representation of a scalar optical wave field without numerical inter-periodic interference in an aperiodic area. The visualization of holographic three-dimensional image light field is presented for the validity of the proposed method. It is believed that the proposed method can be broadly applied to visualization of scalar optical wave field represented by the angular spectrum plane wave bases.

Design of Complex Light Modulation Macro-pixel

Complex modulation architectures for holographic three-dimensional display are investigated. The two contrasted device-level architectures for complex light modulation are analyzed with numerical simulations. The first one takes the form consisting of in-plane amplitude-only pixels, while the second one is made by super-posed pixel structure. The advantage and limitations of the complex light modulation is discussed.