Maksymilian Chlipala

Color holographic display with white light LED source and single phase only SLM

This work presents color holographic display, which is based on a single phase only spatial light modulator (SLM). In the display entire area of the SLM is illuminated by an on-axis white light beam generated by a single large LED. The holographic display fully utilizes SLM bandwidth and has capability of full-color, full frame rate imaging of outstanding quality. This is achieved through: (i) optimal use of the source coherence volume, (ii) application of the single white light LED source, (iii) a development of a novel concept of color multiplexing technique with color filter mask in Fourier plane of the SLM, (iv) and a complex coding with improved diffraction efficiency. Within experimental part of the paper we show single color, full-color holographic 2D and 3D images generated for reconstruction depth exceeding 10 cm.

Resolution limits in holographic display with LED illumination

In presented paper we study the influence of spatial and temporal coherence of light source on resolution and depth of focus of holographic reconstructions. Presented holographic display setup uses phase - only spatial light modulator and realizes complex coding shame which allows to reconstruct objects in volume centered around plane of the modulator. In simulations we implement partially coherent reconstructions of complex hologram theory. It allows to investigate quality of holographic reconstructions for various degree of illuminating light coherence. During experimental tests we validate simulation results. We show that the influence of spatial coherence effect of light source on resolution of reconstructed objects is stronger than that of temporal coherence. Moreover we prove that it is possible to obtain high quality holographic reconstructions for large size source and wide spectrum for objects having large depths.

Full and horizontal parallax Fourier holography with laser capture and LED display

The digital holography and holographic display constitute the best framework of 3D imaging as they aim to recreate the complete optical field emitted by a recorded scene. In this paper, we present two techniques of Fourier holographic imaging of real world objects. The first solution is an end-to-end full color Fourier holographic imaging approach, which involves standard RGB holographic recording an LED-driven viewing window display. It gives possibility of almost undistorted orthoscopic reconstruction of large real objects. Second architecture uses the same digital holographic content and horizontal parallax rainbow holographic display, which has reduced space bandwidth product requirements.

Histogram based hologram binarization for DMD application

In the paper we investigate hologram binarization method through time multiplexing based on histogram. In the proposed approach input object is divided into N components with equal total intensity distributions. Next, propagation and binarization procedure is employed for each component separately. Presented method is matched to DMD application since it modulates the input light simply by reflection. In the computer simulations the quality of the reconstructed holograms with the proposed method is compared with that of the threshold method for different reconstruction distances. Additionally, efficiency of the technique is verified experimentally during optical reconstructions performed in the holographic display with DMD and LED illumination.

Image blur and visual perception for rainbow holographic display

The rainbow hologram provides observation of the reconstructed object with different spectra over different viewing position. Recently, we’ve proposed a concept of digital rainbow holographic display using diffraction grating and white LED lighting source. In the technique, the slit is implemented numerically by reducing the frequency of the hologram, while the rainbow effect is realized by dispersion of white light source on the diffraction grating. Phase only SLM with 4F imaging system is used for implementation of complex wave fields. For classical rainbow hologram, image blur is known to be very important key point regarding holographic image quality. In this paper, we analyze image blur and visual perception for digital rainbow holographic display. The quality of reconstructed rainbow holograms is investigated under varying viewing conditions regarding visual perception and depth resolution. In experiments, the visual properties of the digital rainbow hologram are analyzed using optical reconstructions for the hologram of 3D and 2D objects of different depth.

Fourier Rainbow Holography

We present Fourier rainbow holographic imaging approach. It involves standard laser holographic recording and novel horizontal parallax only holographic display. In the display, the rainbow effect is introduced in an illumination module by high-frequency diffraction grating and white light LED source. The display is addressed by Fourier rainbow digital hologram (FRDH) encoding defocused object field with removed spatial frequency components in one direction by hologram slitting and without spherical phase factor. Theoretically and experimentally it is shown that the method extends the viewing zone of the classical viewing window display in vertical and longitudinal directions, thus the comfort of observation is improved. It is also numerically and experimentally validated that the numerical slitting applied within FRDH generation improves reconstruction depth of the display, here up to 400 mm.

3D color reconstructions in single DMD holographic display with LED source and complex coding scheme

In the paper we investigate the possibility of color reconstructions of holograms with a single DMD and incoherent LED source illumination. Holographic display is built with 4F imaging system centering reconstruction volume around the DMD surface. The display design employs complex coding scheme, which allows reconstructing complex wave from a binary hologram. In order to improve the quality of reconstructed holograms time multiplexing method is used. During the optical reconstructions we analyze quality of reconstructed holograms with incoherent RGB light sources as a function of reconstruction distance, present the possibility of 3D hologram reconstruction, and investigate temporal coherence effects in holographic display with the DMD.

Holographic display with LED sources illumination and enlarged viewing angle

In this work we present holographic display that uses LED sources illumination and have enlarged viewing angle. In this holographic display design we employ phase only SLM because it allows to obtain reconstructions of high quality. Our setup realizes complex coding scheme and allows to reconstruct complex holographic images. Thus reconstruction of inplane holograms is possible. Holograms displayed on SLM are computer generated. For enlargement of angular field of view we use three spatially separated illumination sources and time multiplexing technique. In experimental part, where we display computer generated holograms, we show that it is possible to obtain holographic reconstructions of 3D object with extended viewing angle.

Color reconstructions of real digital holograms in holographic display with white light LED illumination

In this work we investigate the possibility of color reconstructions of digital holograms in holographic display with a white light LED source. The capture system uses RGB laser light and is designed in the Fourier synthetic aperture configuration. The display system uses the LED source and Fresnel configuration with complex coding scheme.

Color reconstructions in holographic display with white light LED illumination and complex modulation

In this work we investigate the holographic display system with white light LED source. We show, that in the system with complex modulation and color filters it is possible to obtain high quality color reconstructions.