Stereoscopic Hologram Joonku Hahn Kyungpook National University
Outline: 1. Introduction - Basic structure of holographic display - Wigner distribution function 2. Design of Stereoscopic Hologram - Optical design concept - Viewing window - Spatial light modulator 3. Examples of Stereoscopic Hologram - Holographic display with a large-scale SLM - Projection-type holographic display - Head-mounted holographic display 4. Summary 1
1. Introduction Available structure of holographic display Coherent Light Source Optics Electrically addressable Spatial Light Modulator Optical filter Scanner Optically addressable Spatial Light Modulator Optics Screen Observer (optional) (optional) 2
1. Introduction Space-bandwidth product N M W W 2 u v u v Data capacity 2 2 Area of image Numerical Aperture wavelength. 2 2 Data capacity Area of screen Field of view wavelength Color depth Space-Bandwidth Product p a p p a p v Spherical phase resulting from d Amplitude contour by sinc function f Pixels of SLM M p W v W u u +1 order diffraction on v-axis Central direction of local viewing angle, c c d Transfer lens N p f Focal plane 0 order diffraction v -1 order diffraction on v-axis u Local viewing angle J. Hahn, H. Kim, Y. Lim, G. Park, and B. Lee, Optics Express 16, pp. 12372-12386, (2008). 3
1. Introduction Wigner distribution function The area in the Wigner distribution function is equal to the space-bandwidth product. v v v x x x After a Fresnel transform After a Fourier transform A. W. Lohmann, R. G. Dorsch, D. Mendlovic, Z. Zalevsky, and C. Ferreira, J. Opt. Soc. Am. A 13, 470-473 (1996). 4
1. Introduction Definition of the planes in holographic display y v x u Hologram plane Viewing window plane 5
1. Introduction Holographic Stereogram vs. Stereoscopic Hologram Hologram plane Viewing window plane Holographic Stereogram Stereoscopic Hologram 6
2. Design of Stereoscopic Hologram Stereoscopic Hologram View volume defined by 8K-resolution hologram 40inch 20inch View volume defined by 4K-resolution hologram View volume defined by 2K-resolution hologram 10inch Transverse resolution at screen p 0.11mm Width of viewing window at pupil of eye w 1.8 m p 8.2 mm @ 0.5 m VW 1.8m 7
2. Design of Stereoscopic Hologram Basic geometry of stereoscopic holographic display Viewing window Hologram plane 8
2. Design of Stereoscopic Hologram Display with a large-aperture SLM Large-aperture SLM Light source Viewing window Hologram plane 9
2. Design of Stereoscopic Hologram Viewing window Spot size of undiffracted light needs to be small enough for fear of disturbing the signal which is modulated by spatial light modulator. 10
2. Design of Stereoscopic Hologram Projection-type display Real image Light source Small-aperture SLM Projection optics with a pair of parabolic mirrors Hologram plane Viewing window 11
2. Design of Stereoscopic Hologram Types and properties of SLM Full-complex modulation Amplitude-only modulation Im i Im i Re -1 1 Re -1 1 Liquid crystal display (LCD) modulator Digital micro-mirror device (DMD) modulator -i Phase-only modulation -i Typical characteristic of liquid crystal device Im i Im i Re -1 1 Re -1 1 Liquid crystal on Silicon (LCoS) modulator Acousto-optic modulator (AOM) -i -i 12
2. Design of Stereoscopic Hologram Off-axis complex hologram encoding with amplitude-only modulation G ( f) 0 G( f) 1 f max (a) fmax f f max (b) fmax f G ( f) 2 G ( f) 3 f max (c) fmax f f max (d) fmax f C.-Y. Hwang, K.-S. Kim, B.-R. Lee, S. Oh, H. Kim, and J. Hahn, Off-axis complex hologram encoding with amplitude-only modulation, Opt. Express submitted. 13
2. Design of Stereoscopic Hologram Structure for off-axis complex hologram encoding with amplitude-only modulation y0 y 1 y 2 y 3 y 4 y5 f1 f2 f3 x 0 x 1 x 2 x 3 x 4 x 5 z d1 d2 f1 d3 d4 d5 SLM plane Focal plane Image plane Viewing window plane 14
2. Design of Stereoscopic Hologram Head-mount display Virtual image SLM Light source Eyepiece Viewing window Hologram plane 15
3. Examples of Stereoscopic Hologram Holographic display with a large-scale SLM Layout Optical design 16
3. Examples of Stereoscopic Hologram Holographic display with a large-scale SLM Structure according to functions EYE Tracking Beamsplitter Main Control Large-scale Spatial Light Modulator I/O ports Hologram Calculation Input Optics Array of Point Light Sources 17
3. Examples of Stereoscopic Hologram Holographic display with a large-scale SLM Motorized stages with light sources array Input integrated optics Spatial light modulators Control boards Large-format beam splitter xin, yin, zin y xout, yout, zout 182mm 144mm 4.55deg z 500mm 1800mm z=-500mm z=0 z=1800mm 18
3. Examples of Stereoscopic Hologram Projection-type holographic display Layout Optical design Viewing windows Holographic display Parabolic mirrors Viewing windows Optics for projection FT lenses SLM Mirrors Light engines 19
3. Examples of Stereoscopic Hologram Projection-type holographic display Light engine Left part Mirrors Right part X-cube prism Green Blue Red SLMs X-cube prism Green Collimators SLMs Collimators Laser diode modules Red FT lenses Filters Blue Laser diode modules Polarizer Objective lens Collimation lens Laser diode module Plate spring Pinhole Adjustable tube (a) Red Green Blue 20
3. Examples of Stereoscopic Hologram Holographic display with a large-scale SLM 10inch screen 21
3. Examples of Stereoscopic Hologram Holographic display with a large-scale SLM Simulation Experiment Focused at the screen Focused 0.9m away from the screen 22
3. Examples of Stereoscopic Hologram Head-mounted holographic display Layout Optical design 23
3. Examples of Stereoscopic Hologram Head-mounted holographic display Data cable Control box with light sources Holographic display for head-mounted application Multimode optical fiber Multimode optical fiber Beamsplitter at viewing window Control board Red LED Blue LED Green LED Data cable Multimode optical fiber 24
x-axis [mm] x-axis [mm] x-axis [mm] 3. Examples of Stereoscopic Hologram x-axis [mm] x-axis [mm] x-axis [mm] x-axis [mm] x-axis [mm] x-axis [mm] Head-mounted holographic display ield on retina Simulation Experiment Complex optical field on retina Complex optical field on retina Complex optical field on retina @1125mm @725mm @1125mm @725mm -0.6-0.6-0.6-0.4 Red -0.2 (625nm) 0-0.4-0.2 0-0.4-0.2 0 0.2 ield on retina 0.2 Complex optical field on retina 0.2 Complex optical field on retina Complex optical field on retina 0.4 0.4 0.4-0.6-0.6-0.6 0.6 0.6 0.6-0.4-0.4-0.4 Green 0.5-1 -0.5 1 0-1 0.5-0.5 1 0 0.5-1 -0.5 1 0 0.5 1 m] -0.2 y-axis [mm] -0.2 y-axis [mm] -0.2 y-axis [mm] (528nm) 0 0 0 0.2 ield on retina 0.2 Complex optical field on retina 0.2 Complex optical field on retina Complex optical field on retina 0.4-0.6 0.6-0.4 Blue (462nm) 0 0.4 0.4-0.6 0.6-0.6 0.6-0.4-0.4 0.5-1 -0.5 1 0-1 0.5-0.5 1 0 0.5-1 -0.5 1 0 0.5 1 m] -0.2 y-axis [mm] -0.2 y-axis [mm] -0.2 y-axis [mm] 0 0 0.2 0.2 0.2 25 0.4 0.6 0.4 0.6 0.4 0.6
4. Summary Stereoscopic hologram has a great potential to display large field through a narrow viewing windows. Optical design of stereoscopic hologram has three possible geometries. The first applies a large-aperture SLM and the second displays a real image of the SLM. The last displays a virtual image of the SLM. We succeeded in constructing several interesting systems under the cooperation with Prof. Kim s group in Korea University. 3 Dimensional Optical Technology I N T E G R A T E D P H O T O N I C D E V I C E S & S Y S T E M S L A B 26