Results 221 to 230 of about 296,849 (299)

Visible Octave Frequency Combs in Silicon Nitride Nanophotonic Waveguides Driven by Ti:Sapphire Lasers

open access: yesLaser &Photonics Reviews, EarlyView.
Chip‐based frequency combs are usually pumped from telecom wavelengths, far from the visible. This work instead pumps close to the visible with a Ti:sapphire laser ‐ the source behind the original optical frequency combs and now becoming chip‐integrable‐ and lets silicon‐nitride waveguides convert it into efficient, octave‐spanning visible‐to‐infrared ...
Abdullah Alabbadi   +5 more
wiley   +1 more source

From Planar to 3D Nanophotonic Lenses: Advancing Design, Fabrication, and Applications

open access: yesLaser &Photonics Reviews, EarlyView.
Three‐dimensional nanophotonic lenses are enabled by an integrated workflow that links design parameterization, full‐wave electromagnetic simulation, computational optimization, and freeform fabrication. This Review summarizes how these tools expand optical design freedom beyond a single patterned plane by enriching the local meta‐atom response and ...
Wei Zhu   +2 more
wiley   +1 more source

Reconfigurable Geometric Phase Matching by Multilayered Nonlinear Thin‐Film Crystals

open access: yesLaser &Photonics Reviews, EarlyView.
The concept of geometric phase matching is demonstrated as a dynamically reconfigurable approach for tunable nonlinear wave mixing in multilayered nonlinear thin‐film crystals. Experimental results reveal full modulation in a bilayer structure and near‐perfect spin‐selective phase matching of second‐harmonic generation in an eight‐layer configuration ...
Danielle Ben‐Haim   +3 more
wiley   +1 more source

Accurate geometric albedo, shape, and size of Hi'iaka from a stellar occultation. [PDF]

open access: yesNat Commun
Fernández-Valenzuela E   +73 more
europepmc   +1 more source

Multispectral Mid‐Infrared Imaging With Incoherent Light via Adiabatic Upconversion

open access: yesLaser &Photonics Reviews, EarlyView.
We demonstrate room‐temperature broadband MIR imaging based on adiabatic frequency upconversion, driven by a Q‐switched pump laser and incoherent illumination. The small‐foot‐print system upconverts the spectral range to the visible domain, without scanning, thermal control and with spatial resolution below 20μm$20\mathrm{\mu}\mathrm{m}$.
Daniel Beitner   +4 more
wiley   +1 more source

Ultimate Intrinsic SNR Depends on B0 Orientation

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose This work aims to investigate the effect of B0$$ {B}_0 $$ orientation on the uiSNR in MRI. Methods Electromagnetic simulations were performed on both realistic body models and simplified geometric models. Comparisons between (1) opposite B0$$ {B}_0 $$ directions along the head‐foot (HF) axis, corresponding to head‐first and feet‐first ...
Yuting Wang   +4 more
wiley   +1 more source

Overmassive black holes and little red dots naturally form in simulations. [PDF]

open access: yesNature
Chon S   +4 more
europepmc   +1 more source

Whole‐Brain Diffusion MRI at 7T With Universal Multiband GRAPE pTx Pulses

open access: yesMagnetic Resonance in Medicine, EarlyView.
Purpose To improve signal strength and homogeneity of whole‐brain diffusion‐weighted imaging (DWI) at 7T. Methods Universal multiband excitation and refocusing pulses were optimized with the gradient ascent pulse engineering (GRAPE) algorithm across a database of B1+$$ {B}_1^{+} $$ and B0$$ {B}_0 $$ maps obtained from 20 subjects.
Marten Laufenberg   +5 more
wiley   +1 more source

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