Results 71 to 80 of about 1,574,076 (309)

Optical Design of a Slitless Astronomical Spectrograph with a Composite Holographic Grism

open access: yesPhotonics, 2023
In the present work, we consider an optical design of a slitless spectrograph for an existing 0.5 m-class telescope. This design concept has a number of advantages such as compact size, simplicity, and simultaneous coverage of a large field of view.
Eduard Muslimov   +6 more
doaj   +1 more source

Dual Optical Hyperbolicity of PdCoO2 and PdCrO2 Delafossite Single Crystals

open access: yesAdvanced Functional Materials, EarlyView.
In this work, the hyperbolic response of PdCoO₂ and PdCrO₂ delafossites is investigated for the first time. They exhibit dual hyperbolic regimes, one localized around a phonon absorption in the mid‐infrared spectral region, and the other extending into the visible range.
Salvatore Macis   +14 more
wiley   +1 more source

Comb-calibrated solar spectroscopy through a multiplexed single-mode fiber channel

open access: yesNew Journal of Physics, 2015
We investigate a new scheme for astronomical spectrograph calibration using the laser frequency comb at the Solar Vacuum Tower Telescope on Tenerife. Our concept is based upon a single-mode fiber channel, that simultaneously feeds the spectrograph with ...
R A Probst   +9 more
doaj   +1 more source

Defects Dynamic in Photo‐Excited CeO2 and their Influence on CO2 Photoreduction

open access: yesAdvanced Functional Materials, EarlyView.
X‐ray photoelectron spectroscopy study under light excitation is presented to track the defect dynamic (Ce4+ to Ce3+) in CeO2. Surface enhanced Raman spectroscopy confirmed the key role of Ce3+ states in controlling charge and energy transfer across the CeO2‐dye molecule interface.
Rambabu Yalavarthi   +3 more
wiley   +1 more source

Manipulating Ferroelectric Topological Polar Structures with Twisted Light

open access: yesAdvanced Materials, EarlyView.
We demonstrate dynamic control of ferroelectric order in quasi‐2D CsBiNb2O7 using twisted ultraviolet light carrying orbital angular momentum. Our approach harnesses non‐resonant multiphoton absorption and induced strain to modulate topological of ferroelectric polarization textures.
Nimish P. Nazirkar   +10 more
wiley   +1 more source

Ultrafast Laser Synthesis of Zeolites

open access: yesAdvanced Materials, EarlyView.
The study presents a novel ultrafast laser‐driven synthesis technique for zeolites directly in liquid. Laser pulses create a microscopic reactor that controls reaction kinetics at femto‐ and picosecond timescales. Nonlinear light‐matter interactions drive nucleation and growth, allowing the process to be paused at any stage of self‐assembly.
Sezin Galioglu   +11 more
wiley   +1 more source

A High-resolution Non-detection of Escaping Helium in the Ultrahot Neptune LTT 9779b: Evidence for Weakened Evaporation

open access: yesThe Astrophysical Journal Letters
The recent discovery of “ultrahot” ( P < 1 day) Neptunes has come as a surprise: some of these planets have managed to retain gaseous envelopes despite being close enough to their host stars to trigger strong photoevaporation and/or Roche lobe overflow ...
Shreyas Vissapragada   +18 more
doaj   +1 more source

Cavity ring down spectroscopy of cold neutral phenanthrene and phenanthridine in supersonic jets

open access: yesAIP Advances, 2019
Here we study the effect of nitrogen insertion on the electronic spectra of polycyclic aromatic hydrocarbon (PAH) molecules measured under laboratory conditions that are relevant for comparison with astronomical data.
Salma Bejaoui, Farid Salama
doaj   +1 more source

Scaling Up Purcell‐Enhanced Self‐Assembled Nanoplasmonic Perovskite Scintillators into the Bulk Regime

open access: yesAdvanced Materials, EarlyView.
This study presents a scalable approach to enhancing bulk scintillators using nanoplasmonics. By integrating 100‐nm silver nanoparticles with perovskite scintillator nanocrystals in a polymer matrix, significant improvements in light yield and decay rates via the Purcell effect are achieved.
Michal Makowski   +16 more
wiley   +1 more source

Overview of the Fiber System for the Dark Energy Spectroscopic Instrument

open access: yesThe Astronomical Journal
The Dark Energy Spectroscopic Instrument (DESI) is a revolutionary instrument designed for precise measurements of cosmic distances and the investigation of dark energy.
Claire Poppett   +68 more
doaj   +1 more source

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