Results 41 to 50 of about 919,980 (236)

Wood‐Derived Nanocellulose‐Biocarbon Fresnel‐Zone Plate Lenses for Sub‐THz Frequency Applications

Advanced Materials Technologies, EarlyView.
Wood‐derived nanocellulose and lignin‐based biocarbon were combined to fabricate fully bio‐based Fresnel zone plate (FZP) lenses for sub‐terahertz frequencies. These sustainable FZP lenses exhibit low dielectric loss and high directivity, achieving performance comparable to that of metallic references, and remain functional under environmental stress ...
Riikka Haataja, Mikko Kokkonen, Niina Halonen, Sami Myllymäki, Umair Rafique, Mandeep Singh, Ossi Laitinen, Heli Jantunen, Kristiina Oksman, Henrikki Liimatainen   +9 more
wiley   +1 more source

Liquid‐Crystal‐Based Reconfigurable Intelligent Surface for 7 GHz Mobile Communication

Advanced Materials Technologies, EarlyView.
The glass‐based liquid‐crystal reconfigurable intelligent surface (LC‐RIS) integrates active‐matrix driving and blind‐greedy phase optimization within a 5G‐NR OFDM framework. This enables continuously tunable and autonomous enhancement of wireless coverage. Leveraging the transparency and manufacturability of liquid crystal panels, it is ideally suited
Tien‐Lun Ting, Yuh‐Chyi Chang, Yi‐Chan Hung, Cheng‐Yuan Hsiao, Chao‐Kai Wen, Tsung‐Hsien Lin   +5 more
wiley   +1 more source

Wavefront curvature sensing and control in microscopy [PDF]

, 2022
The purposes are multiples: creation of a wavefront curvature sensor, use of the curvature sensing to control a multi-actuator lens developed at CNR-IFN of Padua (18 piezoelectric actuators) and use of the multi-actuator lens to generate an astigmatic ...
Dalle Rive, Gianluca
core  

Unlocking Terahertz Steganography: Authentication of Hidden Images in Flexible Media

Advanced Materials Technologies, EarlyView.
Hidden information in multilayered devices, such as steganographic portraits, is detected and authenticated using reflection‐mode terahertz time‐domain imaging. Image reconstruction relies on a dedicated figure‐of‐merit obtained by integrating the signal intensity over the time‐window associated with the reflection from the metallic mirror backing the ...
Tiziana Ritacco, Francesca Vittorioso, Dimitrios C. Zografopoulos, Romeo Beccherelli, Walter Fuscaldo   +4 more
wiley   +1 more source

Interferometric Wavefront Sensing System Based on Deep Learning

Applied Sciences, 2020
At present, most wavefront sensing methods analyze the wavefront aberration from light intensity images taken in dark environments. However, in general conditions, these methods are limited due to the interference of various external light sources.
Yuhao Niu, Zhan Gao, Chenjia Gao, Jieming Zhao, Xu Wang   +4 more
doaj   +1 more source

High speed optical wavefront sensing with low cost fpgas

, 2008
This paper outlines a study into deployment of a parallel processing scheme on an FPGA to meet the needs of high bandwidth processing in adaptive optics wavefront sensing.
Morgan, F., Kepa, K., Coburn, D., Dainty, J.   +3 more
core   +1 more source

Coherent Absorption Reveals Colors Hidden in a Grey Fabry–Pérot Cavity

Advanced Optical Materials, EarlyView.
A dielectric thin film shows colors depending on its thickness; this effect can be used to encode information normally accessible through single‐beam spectroscopy. We developed a method to conceal this kind of information, based on coating the dielectric with a matched conductor, that suppresses the color‐bearing thin‐film resonances.
Giuseppe E. Lio, Giulio Carotta, Lorenzo Lavista, Andrea Camposeo, Giacomo Venturi, Agnese Guernieri, Alessandro Pitanti, Simon A. R. Horsley, Giuseppe C. La Rocca, Alessandro Tredicucci, Simone Zanotto   +10 more
wiley   +1 more source

Photonic integrated circuits for astronomy: A formal description of an integrated photonics-based wavefront sensor (IP-WFS)

Astronomy & Astrophysics
Context. Solar wavefront sensing has been a challenge for astrophysical instrumentalists, due to the low contrast between the Sun and the sky background compared to night-time observations, which limits the performance of adaptive optics systems.
Portero-Rodríguez D., García-Vázquez H., Díaz García J. J., Rodríguez Ramos L. F., Gracia Témich F., Aguerri J. Alfonso L.   +5 more
doaj   +1 more source

Wavefront sensing with critical sampling

, 2011
Different types of nonredundant sampling patterns are shown to guarantee completeness of the basis formed by the sampled partial derivatives of Zernike polynomials, commonly used to reconstruct the wavefront from its slopes (wavefront sensing).
Arines Piferrer, Justo, Rivera, Ricardo, Rafael Navarro, Ricardo Rivera, Navarro, Rafael, Justo Arines   +5 more
core   +1 more source

Using the generalised-optical differentiation wavefront sensor for laser guide star wavefront sensing [PDF]

, 2020
Laser guide stars (LGS) are used in many adaptive optics systems to extend sky coverage. The most common wavefront sensor used in combination with a LGS is a Shack-Hartmann wavefront sensor (SHWFS). The ShackHartmann has a major disadvantage for extended
Dekany, Richard G., Haffert, S.Y., Keller, Christoph U., Keller, C.U., Haffert, Sebastiaan Y., Dekany, R.   +5 more
core   +1 more source