Experimental Aspects of Holographic Projection with a Liquid-Crystal-on-Silicon Spatial Light Modulator

Abstract

Dynamic electroholography is a suitable and promising technology of image display for future projection and near-eye displays. Until a new phase modulation technology is introduced, practical research assumes the use of pixelated spatial light modulators based on liquid crystals with electronically controlled birefringence leading to a controllable refractive index. Such an approach allows for university grade development and testing of holographic computation methodology, but its limitations and drawbacks currently disable the massive application in consumer electronics. This chapter describes the differences between the behavior of the modulator as expected from Fourier optics and that observed in practical optical experiments. Moreover, practical hints and proven techniques of overcoming selected hardware issues of the chosen liquid-crystal-on-silicon (LCoS) phase modulators are given. The smart combination of the described techniques could allow more precise operation of spatial light modulators with a higher agreement with numerical simulations, especially for holographic projection of colorful images.

Three-dimensional visualization of brain tumor progression based accurate segmentation via comparative holographic projection

“…Thus, a predefined light distribution was generated at the observation plane [28,29]. Due to the technical characteristics of the SLM such as the pixelated nature, the limited number of pixels, and the fill factor (less than 100%), there is undesirable effects at the observation plane, for instance, an envelop modulation, a DC term and replicated diffraction orders, these artifacts can be compensated obviously during the design process of the CGH and/or the optical reconstruction [25,26,[28][29][30][31][32][33][34][35]. In addition to the previously mentioned artifacts, there is arising speckle noise that deteriorates the projected image quality in the observation plane which is a result of the coherent light illumination.…”

Distortion correction for wide angle holographic projector

“…A lensless holographic projector built with a phase SLM (Spatial Light Modulator) enables the reconstruction of a high quality, aberration free image [1]. The main limitation of the display is a small projection angle, which is closely related to the pixel pitch of the used SLM.…”