Tunable Optical Beam Deflection Via Liquid Crystal Gradient Refractive Index Generated By Highly Resistive Polymer Film

Shang, Xiaobing; Trinidad, Ailee; Joshi, Pankaj; Smet, Jelle De; Cuypers, Dieter; Smet, Herbert De

doi:10.1109/jphot.2016.2555585

Cited by 16 publications

(13 citation statements)

References 21 publications

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“…A 76% diffraction efficiency was obtained within the maximum deflection range of ±0.34 • . More recently, employing patterned ITO for the conductive electrodes and poly(3, 4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for the resistive electrodes, a maximum steering angle of 4.8 • was achieved, where the steering angle could be varied among many diffraction orders [51]. However, due to the thick cell gap (about 30 µm), the response time was slow (several seconds); further, the efficiency was not very high, as the steered beam spots were gloomy (the exact efficiency was not reported).…”

Section: Resistive Electrodesmentioning

confidence: 99%

Liquid Crystal Beam Steering Devices: Principles, Recent Advances, and Future Developments

et al. 2019

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Continuous, wide field-of-view, high-efficiency, and fast-response beam steering devices are desirable in a plethora of applications. Liquid crystals (LCs)-soft, bi-refringent, and self-assembled materials which respond to various external stimuli-are especially promising for fulfilling these demands. In this paper, we review recent advances in LC beam steering devices. We first describe the general operation principles of LC beam steering techniques. Next, we delve into different kinds of beam steering devices, compare their pros and cons, and propose a new LC-cladding waveguide beam steerer using resistive electrodes and present our simulation results. Finally, two future development challenges are addressed: Fast response time for mid-wave infrared (MWIR) beam steering, and device hybridization for large-angle, high-efficiency, and continuous beam steering. To achieve fast response times for MWIR beam steering using a transmission-type optical phased array, we develop a low-loss polymer-network liquid crystal and characterize its electro-optical properties.

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Section: Resistive Electrodesmentioning

confidence: 99%

Liquid Crystal Beam Steering Devices: Principles, Recent Advances, and Future Developments

et al. 2019

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“…23 Solving the electrical problem can be greatly simplified when assuming that the lateral dimensions are much larger than the thickness d of the LC layer, which in practical realizations is often the case. The typical thickness of the LC layer is in the order of a few lm up to maximum a few tens of lm, while the lateral dimensions range from tens of lm 16 to several millimeter. 13 With this approximation, we need to find an effective permittivity of the liquid crystal layer which is position dependent: e eff ðx; yÞ.…”

Section: Theoretical Modelmentioning

confidence: 99%

“…Such values of the sheet conductivity can be obtained with conductive polymers, such as poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). In the work of Shang et al 16 for example, conductive polymer layers with a sheet resistance of 11 GX/sq are used, equal to a sheet conductivity of about 10 À10 S.…”

Section: Power Consumptionmentioning

confidence: 99%

“…Such a weakly conducting layer approach can be used for tunable lens applications [11][12][13][14] but also for beam steering devices. 15,16 The sheet resistance of weakly conductive layers is an important parameter in the design of several types of devices. It is well known that large area Organic Light Emitting Diode devices (OLEDs) for lighting applications may suffer from a drop in light emission due to the finite sheet conductivity.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of liquid crystal devices based on weakly conductive layers for lensing and beam steering

Beeckman

Nys

Willekens

et al. 2017

Journal of Applied Physics

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Liquid crystals are mostly known for their use in displays, but over the past decade these materials have been applied in a number of other devices such as tunable lenses or beam steering devices. A common technique to realize a gradual electric field profile as is required to obtain a gradual refractive index profile in these applications is the use of weakly conductive materials. The weakly conductive layers are able to spread the voltage profile which is applied through well-conductive electrodes at the side of the weakly conductive layer. The simulation and design of such structures is not trivial because two or three dimensional quasi-static electric field profiles need to be calculated. This is due to the fact that the resistivity of the conductive layers and the dielectric properties of the liquid crystal are coupled. An exact solution requires solving a number of coupled differential equations. In this paper, we develop a model to simulate the RC-effects with an approximate model

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“…One solution is to increase the number of electrodes and decrease the electrode width in each period, which unavoidably results in more complicated driving circuits and processing difficulty. To solve these issues, highly resistive or highly dielectric layers are adopted as an alternative method to smoothen the electric field, leading to more accurate OPD profiles and simpler driving circuits 10, 11 .The other LC beam steering technique utilizes a specifically designed topography on at least one of the confining transparent substrates, i.e. the device has a non-uniform cell gap.…”

Section: Introductionmentioning

confidence: 99%

Fast switching cholesteric liquid crystal optical beam deflector with polarization independence

Shang¹,

Meeus²,

Cuypers³

et al. 2017

Sci Rep

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Optical beam deflectors based on the combination of cholesteric liquid crystals and polymer micro gratings are reported. Dual frequency cholesteric liquid crystal (DFCh-LC) is adopted to accelerate the switching from the homeotropic state back to the planar state. Polarization independent beam steering components are realized whose transmission versus the polarizing angle only varies 4.4% and 2.6% for the planar state and the homeotropic state, respectively. A response time of 451 ms is achieved for DFCh-LC-grating beam deflectors, which is fast compared to other nematic LC beam steerers with similar LC thickness.

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Tunable Optical Beam Deflection Via Liquid Crystal Gradient Refractive Index Generated By Highly Resistive Polymer Film

Cited by 16 publications

References 21 publications

Liquid Crystal Beam Steering Devices: Principles, Recent Advances, and Future Developments

Liquid Crystal Beam Steering Devices: Principles, Recent Advances, and Future Developments

Optimization of liquid crystal devices based on weakly conductive layers for lensing and beam steering

Fast switching cholesteric liquid crystal optical beam deflector with polarization independence

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