Results 61 to 70 of about 109,414 (323)

Replay as wavefronts and theta sequences as bump oscillations in a grid cell attractor network

eLife, 2019
Grid cells fire in sequences that represent rapid trajectories in space. During locomotion, theta sequences encode sweeps in position starting slightly behind the animal and ending ahead of it. During quiescence and slow wave sleep, bouts of synchronized
Louis Kang, Michael R DeWeese
doaj   +1 more source

Fluctuating Curvature and Actuation in 4D Printed Asymmetric Networks by Frontal Photopolymerization

Advanced Materials Interfaces, EarlyView.
Asymmetric polymer networks, fabricated by frontal photopolymerization (FPP), are shown to exhibit curvature oscillations associated with monomer‐solvent exchanges during development and drying. We introduce a theoretical model for such dynamic curvature fluctuations and demonstrate the fabrication of bistable switches and self‐propelled materials that
Muhammad Ghifari Ridwan, Zain Ahmad, Alessandra Vitale, João T. Cabral   +3 more
wiley   +1 more source

Adaptive Shack-Hartmann wavefront sensor accommodating large wavefront variations

Optics Express, 2018
Shack-Hartmann wavefront sensors (SHWFSs) usually have fixed subaperture areas on the detector, in order to fix the minimum and maximum amounts of wavefront departure, or the dynamic range of measurement. We introduce an active approach, named Adaptive Shack Hartmann Wavefront Sensor (A-SHWFS). A-SHWFS is used to reconfigure detection subaperture areas
Maham, Aftab, Heejoo, Choi, Rongguang, Liang, Dae Wook, Kim   +3 more
openaire   +2 more sources

Development of a scalable generic platform for adaptive optics real time control

, 2015
The main objective of the present project is to explore the viability of an adaptive optics control system based exclusively on Field Programmable Gate Arrays (FPGAs), making strong use of their parallel processing capability.
Burse, Mahesh P., Parihar, Padmakar, Ramaprakash, A. N., Surendran, Avinash   +3 more
core   +1 more source

Millisecond‐Switching Dual‐Band/Dual‐Polarization Ka‐Band Wavefront Control Enabled by a Complementary Liquid‐Crystal Metasurface

Advanced Materials Technologies, EarlyView.
An LCD‐compatible complementary liquid‐crystal metasurface delivers dual‐band, dual‐polarized Ka‐band wavefront control with millisecond switching via a 10‐µm LC gap. Interlaced patch/slot pairs enable independent phase tuning at 28 and 38 GHz, while strategic 45° slot rotation suppresses parasitic resonances. Measurements on a 160 × 160‐cell prototype
Daehyeon Kim, Donggeun An, Hyunjae Shin, Youngno Youn, Wonbin Hong   +4 more
wiley   +1 more source

Design and Fabrication of High Dielectric GRIN Lens for a Directive Antenna Using a Hybrid Filled Voxel Additive Manufacturing Technique

Advanced Materials Technologies, EarlyView.
Hybrid‐filled voxel AM enables integration of high‐permittivity materials into additively manufactured devices. Using this approach, a graded refractive index (GRIN) lens is demonstrated, achieving a 50% antenna size reduction with enhanced directivity.
Qianfang Zheng, Anna Radkovskaya, Kailun Xu, Ekaterina Shamonina, Patrick S. Grant   +4 more
wiley   +1 more source

Engineering Thermal Emission with Enhanced Emissivity and Quality Factor Using Bound States in the Continuum and Electromagnetically Induced Absorption

Advanced Optical Materials, EarlyView.
A metal‐based thermal metasurface supporting bound states in the continuum is demonstrated and experimentally shown to achieve a record‐high quality factor of 202 and high emissivity of 0.82. The design offers thermally stable, narrowband mid‐infrared emission, making it ideal for high‐precision gas sensing applications.
Guodong Zhu, Ikjun Hong, Kewei Li, Theodore Anyika, Maxwell T. Ugwu, J. Ryan Nolen, Mingze He, Joshua D. Caldwell, Justus C. Ndukaife   +8 more
wiley   +1 more source

Breaking of Wavelength-Dependence in Holographic Wavefront Sensors Using Spatial-Spectral Filtering

Sensors, 2023
Nowadays, wavefront sensors are widely used to control the shape of the wavefront and detect aberrations of the complex field amplitude in various fields of physics. However, almost all of the existing wavefront sensors work only with quasi-monochromatic
Nikita Stsepuro, Michael Kovalev, Evgenii Zlokazov, Sergey Kudryashov   +3 more
doaj   +1 more source

Phase Topology Stability of an Optical Vortex via an Electrically Controlled Twist‐Planar Oriented Liquid Crystal Fresnel Lens

Advanced Optical Materials, EarlyView.
A simple and efficient method for determining the stability of optical vortices via Fourier transform using a conventional spherical lens is presented. The theoretical and experimental results demonstrate a practical approach to directly and unambiguously measure the magnitude and sign of the topological charge of a beam without altering an ...
Elena Melnikova, Katsiaryna Pantsialeyeva, Dmitry Gorbach, Alexei Tolstik, Sergei Slussarenko Jr., Alina Karabchevsky   +5 more
wiley   +1 more source

An all-photonic focal-plane wavefront sensor

Nature Communications, 2020
Adaptive optics wavefront sensors need to be in a pupil plane and are insensitive to certain wavefront-error modes. The authors present a wavefront sensor based on a photonic lantern fibre-mode-converter and deep learning, which can be placed at the same
Barnaby R. M. Norris, Jin Wei, Christopher H. Betters, Alison Wong, Sergio G. Leon-Saval   +4 more
doaj   +1 more source