High-resolution autostereoscopic immersive imaging display using a monocentric optical system

In 3‐D display system based on opto‐electronic reconstruction of digitally recorded hologram, the field of view of such a system is limited by the spatial resolution of the liquid crystal on silicon (LCOS) spatial light modulator (SLM) used to perform the opto‐electronic reconstruction. In this article, the spatial resolution limitation of LCOS SLM associated with fringe field effect and interpixel coupling is determined by liquid crystal director simulation and Finite Difference Time Domain (FDTD) simulation. The diffraction efficiency loss associates with the imperfection in phase profile is studied with an example of opto‐electronic reconstruction of an amplitude object. A high spatial resolution LCoS SLM with wide reconstruction angle is proposed.

2-D optical phased array (OPA) antenna based on a liquid crystal on silicon (LCOS) spatial light modulator is introduced. Diffraction efficiency of the 1-D OPA for fine angle beam steering and 2-D OPA for aberration correction is characterized experimentally and by computer simulation. Excellent agreement between the simulation, measurement and empirical model is observed. Large aperture transmitter for long distance free space communication is analyzed by wave optics simulation. The system performance for beam steering and correction for wavefront aberration in large aperture transmitter is discussed.

Liquid crystal on silicon (LCoS) spatial light modulators (SLMs) are versatile scientific tools relevant to an increasingly wide variety of research and technological applications including digital holography, wavefront correction, optical tweezing, and non-mechanical beam steering to name a few. Since SLMs are used in a multitude of different ways, some aspects of device performance (e.g., response time) are crucial to certain applications while being irrelevant to others. In this work we couple our standard SLMs with a thermo-electric cooler, allowing for tunability of the device operating temperature from 0° to 75 °C. We show that there is an inherent tradeoff between the liquid crystal response time and the phase stability of an SLM, and that the operating temperature offers a means of controlling this tradeoff. Furthermore, this paper aims to provide the reader with a brief but thorough explanation of SLM operating principles and device structure, defines the performance metrics of the SLM, and provides a methodology for measuring the specifications. By allowing control over the SLM operating temperature and detailing how temperature affects device functionality, SLM users are afforded greater experimental flexibility and will be better able to tailor the performance of their device for the given project or application at hand.

Surface-stabilized antiferroelectric liquid crystals (AFLCs) and V-shape smectics share the spontaneous generation of intermediate transmission states, i.e. analogue grayscale. On the other hand, liquid crystal on silicon (LCOS) appears to be a promising alternative to thin-film transistors (TFTs) in the preparation of reflective microdisplays and spatial light modulators (SLMs). The feasibility of preparing LCOS SLMs using AFLC and V-shaped LCs has been analyzed. A comparative study of a number of AFLC and V-shape materials as candidates for LCOS SLMs has been carried out. Test cells below 1 µm have been prepared using an ITO-coated transparent glass plate and an aluminized silicon back plate mimicking the actual LCOS device. AFLC waveforms compatible to low-voltage operation of the silicon backplane have been demonstrated. V-shape waveforms have been designed and demonstrated as well. The results show that both LC families may be employed in this specific application. Dynamic behavior, with frame rates over 200 Hz, is especially remarkable.

We present a method for reducing the phase flicker originated by the pulsed modulation of a Liquid Crystal on Silicon (LCoS) Spatial Light Modulator (SLM). It consists in reducing the temperature of the LCoS in a controlled way, in order to increase the viscosity of the liquid crystal. By doing this, we increase the time response of the liquid crystal, and thus reduce the amplitude of phase fluctuations. We evaluate the efficacy of this method quantifying the temporal evolution of phase shift using an experiment that is insensitive to optical polarization fluctuations. Additionally, we determine the effect of the temperature reduction on the effective phase modulation capability of the LCoS. We demonstrate that a reduction of up to 80% of the flicker initial value can be achieved when the LCoS is brought to -8 °C.

A novel imaging technique that produces accurate amplitude and phase images of an optical fiber facet using only a phase-only liquid-crystal on silicon (LCOS) spatial light modulator (SLM) and a single-pixel detector is presented. The system can take images in two orthogonal polarizations and so provides a powerful tool for modal characterization of multimode fibers, which is of increasing importance due to their burgeoning use in telecommunications and medical applications. This technique first uses a simulated annealing algorithm to compute a hologram that collects light from a small region of the fiber facet. Next, the fiber facet is automatically brought into focus using adaptive aberration correction on the SLM. Finally, a common-path interferometer is created using the SLM, and the phase of the optical field at each pixel is determined. Finally, high-definition amplitude and phase images of a ring-core refractive index fiber are presented as a proof-of-principle demonstration of the technique.

Liquid Crystal on Silicon (LCoS) Spatial Light Modulators (SLMs) are used as programmable adaptive optical elements1,2,3 in many applications involving high power lasers. In some cases, LCoS SLMs may be exposed to laser radiation that can cause permanent, irreparable damage to the SLM. The damage arises from a number of parameters including laser wavelength, pulse duration, pulse repetition rate, beam diameter, spatial profile, temporal profile, and even angle of incidence. This paper is an introduction and practical guide to understanding laser damage mechanisms and expected damage threshold levels for LCoS SLMs.

The cavity supports the orthogonal reference beam families as its eigenmodes while enhancing the reference beam power. Such orthogonal eigenmodes are used as additional degree of freedom to multiplex data pages, consequently increase storage densities for volume Holographic Data Storage Systems (HDSS) when the maximum number of multiplexed data page is limited by geometrical factor. Image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe:LiNbO3 medium with a 532 nm laser at multiple Bragg angles by using Liquid Crystal on Silicon (LCOS) spatial light modulators (SLMs) in reference arms. Total of nine holograms are recorded with three angular and three eigenmode.

We have developed a high-resolution, multi-color retinal imaging system using liquid crystal adaptive optics. A liquid crystal on silicon (LCOS) spatial light modulator (SLM) is used to correct ocular aberrations. In order to compensate for the dependency of an LCOS SLM on optical wavelength and acquire aberration-corrected images at different color, we apply an open-loop technique. In the open-loop technique, the imaging light is separated from the sensing light and the optimal phase modulation is applied only to the imaging light while the sensing light is not phase-modulated. With the system, in vivo imaging of the human retina is achieved by using illumination light at wavelength of 655nm and 593nm and sensing light at 780nm. Photoreceptors are clearly revealed at each illumination wavelength with the liquid crystal adaptive optics.

Linear structured illumination microscopy (SIM) is a super-resolution microscopy technique that does not impose photophysics requirements on fluorescent samples. Multicolor SIM implementations typically rely on liquid crystal on silicon (LCoS) spatial light modulators (SLM's) for patterning the excitation light, but digital micromirror devices (DMD's) are a promising alternative, owing to their lower cost and higher speed. However, existing coherent DMD SIM implementations use only a single wavelength of light, limited by the lack of efficient approaches for solving the blazed grating effect for polychromatic light. We develop the requisite quantitative tools, including a closed form solution of the blaze and diffraction conditions, forward models of DMD diffraction and pattern projection, and a model of DMD aberrations. Based on these advances, we constructed a three-color DMD microscope, quantified the effect of aberrations from the DMD, developed a high-resolution optical transfer function measurement technique, and demonstrated SIM on fixed and live cells. This opens the door to applying DMD's in polychromatic applications previously restricted to LCoS SLM's.

In this paper we present a method for topography measurement of high gradient reflective microstructures that overcomes the limited numerical aperture (NA) of a digital holographic (DH) system working in reflection. We consider a case when a DH system is unable to register the light reflected from the full sample area due to insufficient NA. To overcome this problem, we propose digital holography in a microscope configuration with an afocal imaging system and a modified object arm in the measurement setup. The proposed modification includes application of a spatial light modulator (SLM) based on liquid crystal on silicon (LCoS) technology for multidirectional plane wave illumination. The variable off-axis illumination enables characterization of the sample regions that cannot be imaged by the limited NA of a classical DH system utilizing on-axis illumination. In the proposed method, the final object topography is merged from a set of captured object waves corresponding to various illumination directions using a novel automatic algorithm. The proposed technique is experimentally validated by full-field measurement of a silicon mold with a high gradient of shape.

A variety of methods have been developed in the last years to generate vector beams. In this work we will present some techniques that we have developed for the efficient and compact generation of arbitrary polarized vector beams. They are based on the use of geometric-phase elements combined with liquid-crystal on silicon (LCOS) spatial-light modulators (SLM) in a common-path architecture. LCOS-SLMs were used to encode a phase-only diffractive mask that encodes complex functions with high diffraction efficiency. We demonstrate the generation of arbitrary scalar modes and vector beam modes.

A liquid crystal panel for a video projector is often used for holographic television. However, its pixel size and pixel number are not enough for practical holographic 3-D display. Therefore, a multipanel configuration is generally used to increase the viewing window and displayed image size, and many spatial light modulators should be used in them. We propose a novel method to increase the viewing window of a holographic display system. The proposed method, which is implemented by using a mirror module and 4-f lens set, is to reconfigure the beam shape reflected by a spatial light modulator. The equipment is applied to a holographic display system, which has only a single spatial light modulator; a hologram could be displayed in a wider viewing window by the equipment than that of the conventional method. By the proposed method, the resolution of the reconfigured spatial light modulator has double resolution in the horizontal direction. Inversely, the vertical resolution is decreased. Even if the vertical resolution is decreased, a viewer could get 3-D effect because humans get more 3-D information in the horizontal direction. We have experimented using a liquid crystal on silicon (LcOS), whose resolution is 4096×2160 pixels. The reconfigured resolution by the mirror module is 8192×1080 pixels. From the experiments, the horizontal viewing window is almost two times wider than that without the mirror module. As a result, the hologram can be observed binocularly.

Many advancements in the fields of holographic displays, image projection, and structured illumination rely on phase-only spatial light modulators (SLMs) to generate light fields with high dynamic range and little light loss. However, commonly used Liquid Crystal on Silicon (LCoS) SLMs are typically slow (<120Hz), while SLMs which can be modulated faster tend to have limited diffraction efficiency or binary bit depth. Recently, a new class of MEMS devices, Phase Light Modulators (PLMs), have shown promise for fast (>5 kHz) holographic illumination and display technologies. However, their bit depth is still limited to four-to-five bits, causing many light field modulation and optimization methods, such as Gerchberg-Saxton phase retrieval, to produce poor-quality results. In this contribution, we introduce an iterative modulation algorithm which combines a four-phase PLM level averaging method with Gerchberg-Saxton phase retrieval to enable complex field modulation while simultaneously improving the bit depth of the modulator, the PSNR of projected images, and contrast of projected images.

Digital Electro-optics Platform is the main concept of Jasper Display Corp. (JDC) to develop various applications. These applications are based on our X-on-Silicon technologies, for example, X-on-Silicon technologies could be used on Liquid Crystal on Silicon (LCoS), Micro Light-Emitting Diode on Silicon (μLEDoS), Organic Light-Emitting Diode on Silicon (OLEDoS), and Cell on Silicon (CELLoS), etc. LCoS technology is applied to Micro Display, Spatial Light Modulator (SLM), Dynamic Optics, Wavelength Selective Switch (WSS), Holographic Display, Microscopy, Bio-tech, 3D Printing and Adaptive Optics, etc. In addition, μLEDoS technology is applied to Augmented Reality (AR), Head Up Display (HUD), Head-mounted Display (HMD), and Wearable Devices.