Tunable-focus flat liquid crystal spherical lens

Ren, Hongwen; Fan, Yun‐Hsing; Gauza, Sebastian; Wu, Shin‐Tson

doi:10.1063/1.1760226

Cited by 198 publications

(91 citation statements)

References 13 publications

(14 reference statements)

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“…In the variable index of reflection approach, lens shape is fixed and the index of refraction is controlled by applying an electric field [21]. We focus our attention on the lenses based on the deformable surface approach (which we refer to as deformable lenses) due to their larger aperture size and superior dynamic response.…”

Section: Introductionmentioning

confidence: 99%

Focal sweep videography with deformable optics

Miau

Cossairt

Nayar

2013

IEEE International Conference on Computational Photography (ICCP)

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A number of cameras have been introduced that sweep the focal plane using mechanical motion. However, mechanical motion makes video capture impractical and is unsuitable for long focal length cameras. In this paper, we present a focal sweep telephoto camera that uses a variable focus lens to sweep the focal plane. Our camera requires no mechanical motion and is capable of sweeping the focal plane periodically at high speeds. We use our prototype camera to capture EDOF videos at 20f ps, and demonstrate space-time refocusing for scenes with a wide depth range. In addition, we capture periodic focal stacks, and show how they can be used for several interesting applications such as video refocusing and trajectory estimation of moving objects.

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Section: Introductionmentioning

confidence: 99%

Focal sweep videography with deformable optics

Miau

Cossairt

Nayar

2013

IEEE International Conference on Computational Photography (ICCP)

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“…Such a laterally varying OPL-profile is obtained by applying a non-uniform electric field over a liquid crystal. Inhomogeneous fields can be obtained with lenticulars [1][2][3] and hole-patterned arrays [4], which typically require only two electrodes, but also with multi-electrode designs. The latter category allows for a more accurate control of the phase front and can e.g.…”

Section: Introductionmentioning

confidence: 99%

Ferroelectric thin films with liquid crystal for gradient index applications

Willekens¹,

George²,

Neyts³

et al. 2016

Opt. Express

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We report on the first ever combination of a thin film of lead zirconate titanate (PZT) with a liquid crystal (LC) layer. Many liquid crystal applications use a transparent conductive oxide to switch the liquid crystal. Our proposed processing does not, instead relying on the extremely high dielectric constant of the ferroelectric layer to extend the electric field from widely spaced electrodes over the liquid crystal. It eliminates almost entirely the fringe field problems that arise in nearly all the liquid crystal devices that use multiple addressing electrodes. We show, both via rigorous simulations as well as experiments, that the addition of a PZT layer over the addressing electrodes leads to a markedly improved LC switching performance at distances of up to 30 µm from the addressing electrodes with the current PZT-layer thickness of 0.84 µm. This improvement in switching is used to tune the focal length of the microlens with electrodes spaced at 30 µm.

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“…6 Many approaches have been demonstrated to also build nematic LC (NLC) components for optical imaging. 1,[7][8][9][10][11][12][13][14][15][16][17] However, those materials have a fundamental limitation: they are polarization sensitive since the refractive index modulation here is achieved by the electrical field-induced reorientation of their local anisotropy axis (commonly called "director," representing the local average direction of the long molecular axes of the NLC 4 ). Figure 1(a) schematically demonstrates an electrically variable NLC lens using a single-layer of NLC that is in the Y; Z plane (with its ground state director being parallel with the Y-axis).…”

Section: Introductionmentioning

confidence: 99%

Focusing unpolarized light with a single-nematic liquid crystal layer

Galstian

Allahverdyan

2015

Opt. Eng

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Abstract. We describe a simple but very efficient optical device that allows the dynamic focusing of unpolarized light using a single-nematic liquid crystal layer. The operation principle of the proposed device is based on the combination of an electrically variable "half-lens" with two fixed optical elements for light reflection and a 90-deg polarization flip. Such an approach is made possible thanks to the close integration of the thin film wave plate and mirror. Preliminary experimental studies of the obtained electrically variable mirror show very promising results. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Tunable-focus flat liquid crystal spherical lens

Cited by 198 publications

References 13 publications

Focal sweep videography with deformable optics

Focal sweep videography with deformable optics

Ferroelectric thin films with liquid crystal for gradient index applications

Focusing unpolarized light with a single-nematic liquid crystal layer

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