Pixel-level fringing-effect model to describe the phase profile and diffraction efficiency of a liquid crystal on silicon device

Lu, Tianxin; Pivnenko, Mykhaylo; Robertson, Brian; Chu, Daping

doi:10.1364/ao.54.005903

Cited by 36 publications

(17 citation statements)

References 18 publications

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“…The reason for this limitation is that downsizing the pixels further while keeping the required thickness of LC layer introduces a cross-talk between the pixels, owing to the broadened phase profile and high level of detrimental fringing fields. [6][7][8][9][10] This, in turn, limits the field of view (FOV) of the SLM, which is defined as the angular coverage of the first diffractive order, inversely proportional to the pixel size, and represents one of the most important figure of merits (FOMs) for phase-only SLMs. This problem is more severe for transmissive SLMs, which have a smaller filling factor due to the space occupied by transistors and an LC thickness that is twice larger than that of reflective SLMs to obtain the same phase accumulation.…”

Section: Introductionmentioning

confidence: 99%

Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

Veetil

et al. 2019

Science

464

371

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Rapidly developing augmented reality (AR) and 3D holographic display technologies require spatial light modulators (SLM) with high resolution and viewing angle to be able to satisfy increasing customer demands. Currently available SLMs, as well as their performance, are limited by their large pixel sizes of the order of several micrometres. Further pixel size miniaturization has been stagnant due to the persistent challenge to reduce the inter-pixel crosstalk associated with the liquid crystal (LC) cell thickness, which has to be large enough to accumulate the required 2π phase difference. Here, we propose a concept of tunable dielectric metasurfaces modulated by a liquid crystal environment, which can provide abrupt phase change and uncouple the phase accumulation from the LC cell thickness, ultimately enabling the pixel size miniaturization. We present a proof-of-concept metasurface-based SLM device, configured to generate active beam steering with >35% efficiency and large beam 2 deflection angle of 11°, with LC cell thickness of only 1.5 μm, much smaller than conventional devices. We achieve the pixel size of 1.14 μm corresponding to the image resolution of 877 lp/mm, which is 30 times larger comparing to the presently available commercial SLM devices.High resolution and viewing angle of the metasurface-based SLMs opens up a new path to the next generation of near-eye AR and 3D holographic display technologies.

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Section: Introductionmentioning

confidence: 99%

Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

Veetil

et al. 2019

Science

464

371

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“…This equation is widely used for fast calculation of the expected diffraction efficiency. In another model built by Lu et al [57], the near field phase profile of the grating is observed under a microscope. The profile is then fitted using the error function, and the diffraction efficiency is calculated by the angular spectrum method.…”

Section: Fringing Field Effectmentioning

confidence: 99%

LCoS SLM Study and Its Application in Wavelength Selective Switch

et al. 2017

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Abstract:The Liquid-Crystal on Silicon (LCoS) spatial light modulator (SLM) has been used in wavelength selective switch (WSS) systems since the 1990s. However, most of the LCoS devices used for WSS systems have a pixel size larger than 6 µm. Although there are some negative physical effects related to smaller pixel sizes, the benefits of more available ports, larger spatial bandwidth, improved resolution, and the compactness of the whole system make the latest generation LCoS microdisplays highly appealing as the core component in WSS systems. In this review work, three specifications of the WSS system including response time, crosstalk and insertion loss, and optimization directions are discussed. With respect to response time, the achievements of liquid crystal material are briefly surveyed. For the study of crosstalk and insertion loss, related physical effects and their relation to the crosstalk or insertion loss are discussed in detail, preliminary experimental study for these physical effects based on a small pixel LCoS SLM device (GAEA device, provided by Holoeye, 3.74 µm pixel pitch, 10 megapixel resolution, telecom) is first performed, which helps with predicting and optimizing the performance of a WSS system with a small pixel size SLM. In the last part, the trend of LCoS devices for future WSS modules is discussed based on the performance of the GAEA device. Tradeoffs between multiple factors are illustrated. In this work, we present the first study, to our knowledge, of the possible application of a small pixel sized SLM as a switching component in a WSS system.

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“…Besides the effects produced by the limited electronics bandwidth already described, interpixel effects in the LC layer may also cause a reduction in the spatial frequency bandwidth. These interpixel effects are the fringing-field (i.e., appearance of tangential components in the applied electric field) and vicinity LC adherence effects that appear as a result of the competition between the tangential components of the applied field and the intermolecular forces within the liquid crystals (i.e., avoiding abrupt changes in the orientation) [16][17][18][19][20][21][22]. These interpixel effects are becoming more and more important in modern LCoS devices as the pixel size is becoming increasingly small, even smaller than 4 µm [22], thus decreasing the ratio between the pixel size and the LC layer thickness (i.e., the cell gap).…”

Section: Introductionmentioning

confidence: 99%

Anamorphic and Local Characterization of a Holographic Data Storage System with a Liquid-Crystal on Silicon Microdisplay as Data Pager

et al. 2018

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In this paper, we present a method to characterize a complete optical Holographic Data Storage System (HDSS), where we identify the elements that limit the capacity to register and restore the information introduced by means of a Liquid Cristal on Silicon (LCoS) microdisplay as the data pager. In the literature, it has been shown that LCoS exhibits an anamorphic and frequency dependent effect when periodic optical elements are addressed to LCoS microdisplays in diffractive optics applications. We tested whether this effect is still relevant in the application to HDSS, where non-periodic binary elements are applied, as it is the case in binary data pages codified by Binary Intensity Modulation (BIM). To test the limits in storage data density and in spatial bandwidth of the HDSS, we used anamorphic patterns with different resolutions. We analyzed the performance of the microdisplay in situ using figures of merit adapted to HDSS. A local characterization across the aperture of the system was also demonstrated with our proposed methodology, which results in an estimation of the illumination uniformity and the contrast generated by the LCoS. We show the extent of the increase in the Bit Error Rate (BER) when introducing a photopolymer as the recording material, thus all the important elements in a HDSS are considered in the characterization methodology demonstrated in this paper.

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Pixel-level fringing-effect model to describe the phase profile and diffraction efficiency of a liquid crystal on silicon device

Cited by 36 publications

References 18 publications

Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

LCoS SLM Study and Its Application in Wavelength Selective Switch

Anamorphic and Local Characterization of a Holographic Data Storage System with a Liquid-Crystal on Silicon Microdisplay as Data Pager

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