Time-bandwidth product of the acousto-optical cell based on a TeO2-crystal

AbstractElectro-optical cell based on the cholesteric liquid crystal is studied with unique combination of the boundary conditions: conical anchoring on the one substrate and planar anchoring on another one. Periodic structures in cholesteric layer and their transformation under applied electric field are considered by polarizing optical microscopy, the experimental findings are supported by the data of the calculations performed using the extended Frank elastic continuum approach. Such structures are the set of alternating over- and under-twisted defect lines whose azimuthal director angles differ by $$180^\circ$$ 180 ∘ . The $$U^+$$ U + and $$U^-$$ U - -defects of periodicity, which are the smooth transition between the defect lines, are observed at the edge of electrode area. The growth direction of defect lines forming a diffraction grating can be controlled by applying a voltage in the range of $$0\le \, V \le 1.3$$ 0 ≤ V ≤ 1.3 V during the process. Resulting orientation and distance between the lines don’t change under voltage. However, at $$V>1.3$$ V > 1.3 V $$U^+$$ U + -defects move along the defect lines away from the electrode edges, and, finally, the grating lines collapse at the cell’s center. These results open a way for the use of such cholesteric material in applications with periodic defect structures where a periodicity, orientation, and configuration of defects should be adjusted.

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Complex Wavefront Shaping through a Multi-Core Fiber

Applied Sciences ◽

10.3390/app11093949 ◽

2021 ◽

Vol 11 (9) ◽

pp. 3949

Author(s):

Jiawei Sun ◽

Nektarios Koukourakis ◽

Jürgen W. Czarske

Keyword(s):

Phase Retrieval ◽

Light Field ◽

Discrete Distribution ◽

Cell Manipulation ◽

Retrieval Algorithm ◽

Optical Cell ◽

Loop Control ◽

Wavefront Shaping ◽

Core Fiber ◽

Phase Retrieval Algorithm

Wavefront shaping through a multi-core fiber (MCF) is turning into an attractive method for endoscopic imaging and optical cell-manipulation on a chip. However, the discrete distribution and the low number of cores induce pixelated phase modulation, becoming an obstacle for delivering complex light field distributions through MCFs. We demonstrate a novel phase retrieval algorithm named Core–Gerchberg–Saxton (Core-GS) employing the captured core distribution map to retrieve tailored modulation hologram for the targeted intensity distribution at the distal far-field. Complex light fields are reconstructed through MCFs with high fidelity up to 96.2%. Closed-loop control with experimental feedback denotes the capability of the Core-GS algorithm for precise intensity manipulation of the reconstructed light field. Core-GS provides a robust way for wavefront shaping through MCFs; it facilitates the MCF becoming a vital waveguide in endoscopic and lab-on-a-chip applications.

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Design of an optical cell for pulse radiolysis of supercritical water

Review of Scientific Instruments ◽

10.1063/1.1288258 ◽

2000 ◽

Vol 71 (9) ◽

pp. 3345-3350 ◽

Cited By ~ 21

Author(s):

Kenji Takahashi ◽

Jason A. Cline ◽

David M. Bartels ◽

Charles D. Jonah

Keyword(s):

Supercritical Water ◽

Pulse Radiolysis ◽

Optical Cell

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