Polarization-controlled switching between diffraction orders in transverse-periodically aligned nematic liquid crystals

Sarkissian, H.; Serak, Svetlana V.; Tabiryan, Nelson V.; Glebov, L. B.; Rotar, Vasile; Zel'dovich, Boris Ya

doi:10.1364/ol.31.002248

Cited by 89 publications

(44 citation statements)

References 6 publications

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“…Experimental results starting in 2004 were promising, 8 but were plagued by pervasive defects crippling their optical properties due to poor LC alignment. More recent work 13 reported in 2006 continued to show substantial scattering due to the presence of disclinations and random defects and achieved only < 18% efficiency .…”

Section: Introductionmentioning

confidence: 95%

A polarization-independent liquid crystal spatial light modulator

Escuti

Jones

2006

SPIE Proceedings

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We report our recent experimental results on a new polarization-independent, liquid crystal (LC) spatial light modulator (SLM). Based on a periodic nematic director profile, the modulator acts as a switchable diffraction grating with only 0 th -and ±1 st -orders at efficiencies of ≥ 99%, manifests contrast ratios ∼600:1 (for laser light), switching times of ∼ 2ms, and threshold voltages of < 1V /µm. Results of modulating broadband, unpolarized light from light-emitting-diodes (LEDs) indicates that contrast ratios are ∼100:1 so far. Note that incoherent scattering for visible light is very low, and that samples are typically completely defect-free over large areas. An important feature of this diffractive polarization-independent SLM compared to its predecessors is its potential to achieve much larger diffraction angles, which enables a larger aperture (andétendue). In addition to describing the fabrication and characteristics of this SLM in general, we report on our initial progress in implementing a projection display system. All of the surprising and useful results from this grating arise from its continuous nematic director, which is most properly classed as a switchable polarization grating (PG). The SLM described here offers the inherent advantages polarization-independence at the pixel-level and fairly fast switching with nematic LCs, while maintaining similar switching voltages, cell thickness, contrast ratios, and materials.

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Section: Introductionmentioning

confidence: 95%

A polarization-independent liquid crystal spatial light modulator

Escuti

Jones

2006

SPIE Proceedings

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“…This simplification restricts the underlying diffeomorphic map to the family of quasi-conformal maps [5]. However, inspired by optical axes grating in liquid crystals [6,7], one can show [8] that the diffeomorphic map between the virtual space and physical space might extend to the family of the area-preserving maps by sequentially manipulating the direction of optical axes instead of gradually changing the amplitude of refractive index.…”

Section: Introductionmentioning

confidence: 99%

Curved Space-Time for Light by an Anisotropic Medium: Media With the Variable Optical Axes

Mousavi¹,

Roknizadeh²,

Sahebdivan³

et al. 2016

PIER M

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Abstract-An optical impedance-matched medium with a gradient refractive index can resemble a geometrical analogy with an arbitrary curved space-time. In this paper, we show that a non-impedancematched medium with a varying optical axis can also resemble the features of a space of non-trivial metric for the light. The medium with a varying optical axis is an engineered stratified slab of material, in which the orientation of the optical axis in each layer slightly differs from the other layers, while the magnitude of refractive index remains constant. Instead of the change in refractive index, the inhomogeneity of such a medium is induced by the local anisotropy. Therefore, the propagation of light depends on the local optical axis. We study the conditions that make the analogy between curved spacetime and a medium with a varying optical axis. Extension of the transformation optics to the media with optical axis profile might ease some fabrication difficulties of materials with gradient refractive index.

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“…In this example for a =1.6 m laser (optimized for methane detection) that is launched from a satellite at an altitude of 400 km to have a 1/e 2 diameter spot of 5 meters on the Earth the 1/e 2 diameter of the launch aperture must be approximately 15 cm. 15 Additionally, from an altitude of 400 km, to have a 5 km wide swath on the Earth the output must scan over approximately 0.7 o . This is equivalent to stating that the scanner must have 1000 resolvable spots (Nspots=1000) in the far-field.…”

Section: Introductionmentioning

confidence: 99%

Liquid crystal clad waveguide laser scanner and waveguide amplifier for LADAR and sensing applications

et al. 2015

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We will describe the construction and performance of a prototype high speed, non-mechanically scanned, laser system that is coupled to a custom planar waveguide optical amplifier. The system provides high speed (10 kHz) scanning of >200 far-field resolvable spots, with a path toward >500 spots at 10 kHz demonstrated. An enabling component for this system is the new EO scanner that provides previously unrealizable performance such as sub-millisecond scanning, full 2-D operation with only three control electrodes, fully refractive (no side-lobes) scanning, no blind spot within the field of view (FOV), and a large continuous scan angle. Scanners with near perfect Gaussian output beams, throughputs greater than 50%, and a 50 0 × 15 o continuous field-of-view will be discussed. Furthermore, a path toward much larger FOVs will also be presented. We will also present the design and construction of custom planar waveguide amplifiers to which our EO scanner can be free space end-fire coupled. The amplifiers and scanners were designed for operation at 1.645 microns. This will enable long-range, eye-safe LADAR and sensing applications, such as CH4 sensors.

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Polarization-controlled switching between diffraction orders in transverse-periodically aligned nematic liquid crystals

Cited by 89 publications

References 6 publications

A polarization-independent liquid crystal spatial light modulator

A polarization-independent liquid crystal spatial light modulator

Curved Space-Time for Light by an Anisotropic Medium: Media With the Variable Optical Axes

Liquid crystal clad waveguide laser scanner and waveguide amplifier for LADAR and sensing applications

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