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Femtosecond time-resolved mid-infrared reflectivity is used to investigate the electron and phonon dynamics occurring at the direct band gap of the excitonic insulator Ta$_2$NiSe$_5$ below the critical temperature of its structural phase…

We investigate the low temperature transport in 8 nm diameter Si junctionless nanowire field effect transistors fabricated by top down techniques with a wrap-around gate and two different activated doping densities. First we extract the…

Mesoscale and Nanoscale Physics · Physics 2019-01-02 Felix J. Schupp , Muhammad M. Mirza , Donald A. MacLaren , G. Andrew D. Briggs , Douglas J. Paul , Jan A. Mol

We formulate a multi-physics model to describe the nonlinear propagation of a femtosecond, near-infrared, tightly focused laser pulse in a transparent dielectric. The application of our model to the case of bulk sapphire shows that even…

Optics · Physics 2023-07-11 Anton Rudenko , Jerome V. Moloney , Pavel Polynkin

Nanowires have unique optical properties [1-4] and are considered as important building blocks for energy harvesting applications such as solar cells. [2, 5-8] However, due to their large surface-to-volume ratios, the recombination of…

Mesoscale and Nanoscale Physics · Physics 2011-05-26 Yaping Dan , Kwanyong Seo , Kuniharu Takei , Jhim H. Meza , Ali Javey , Kenneth B. Crozier

Simultaneous measurements of transient transmission and reflectivity were performed in the unintentionally doped InN film to reveal ultrafast optical bleaching and its recovery behavior under intense laser irradiation. The optical bleaching…

Optics · Physics 2021-02-16 Junjun Jia , Takashi Yagi , Toshiki Makimoto

The early stage of the reactive interdiffusion in the Cu-Al system was investigated at 350 {\textdegree}C and 300 {\textdegree}C thanks to in-situ transmission electron microscopy. A special care was given to find conditions where the…

Materials Science · Physics 2020-05-08 F. Moisy , X. Sauvage , E. Hug

The coherent spin dynamics of electrons and holes are studied in a FA0.9Cs0.1PbI2.8Br0.2 perovskite bulk crystal, using time-resolved Kerr ellipticity in a two-color pump-probe scheme. The probe photon energy is tuned to the exciton…

We probe the electron transport properties in the shell of GaAs/In0.2Ga0.8As core/shell nanowires at high electric fields using optical pump / THz probe spectroscopy with broadband THz pulses and peak electric fields up to 0.6 MV/cm. The…

Mesoscale and Nanoscale Physics · Physics 2020-06-24 Rakesh Rana , Leila Balaghi , Ivan Fotev , Harald Schneider , Manfred Helm , Emmanouil Dimakis , Alexej Pashkin

We present a novel experimental protocol using Cathodoluminescence measurements as a function of the electron incident energy to study both exciton diffusion in a directional way and surface exciton recombination. Our approach overcomes the…

We describe the generation of powerful dispersive waves that are observed when pumping a dual concentric core microstructured fiber by means of a sub-nanosecond laser emitting at the wavelength of~1064 nm. The presence of three zeros in the…

The dynamics of charge carriers in amorphous semiconductors fundamentally differ from those in crystalline semiconductors due to the lack of long-range order and the high defect density. Despite intensive technology-driven research…

Materials Science · Physics 2017-10-11 Bolin Liao , Ebrahim Najafi , Heng Li , Austin J. Minnich , Ahmed H. Zewail

Dispersion engineering in silicon nitride (SiX NY ) waveguides is investigated through the optimization of the waveguide transversal dimensions and refractive indices in a multi-cladding arrangement. Ultra-flat dispersion of -84.0 +/- 0.5…

Metals exhibit nonequilibrium electron and lattice subsystems at transient times following femtosecond laser excitation. In the past four decades, various optical spectroscopy and time-resolved diffraction methods have been used to study…

Chemical Physics · Physics 2024-05-17 Xing He , Mithun Ghosh , Ding-Shyue Yang

Semiconducting single-walled carbon nanotubes are studied in the diffusive transport regime. The peak mobility is found to scale with the square of the nanotube diameter and inversely with temperature. The maximum conductance, corrected for…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Xinjian Zhou , Ji-Yong Park , Shaoming Huang , Jie Liu , Paul L. McEuen

A nanometer-thin-cell (in the direction of laser beam propagation) has been elaborated with the thickness of the atomic vapor column varying smoothly in the range of $L = \unit[50-1500]{nm}$. The cell allows one to study the behavior of the…

Atomic Physics · Physics 2016-04-20 A. Sargsyan , Y. Pashayan-Leroy , C. Leroy , D. Sarkisyan

Ultra-intense laser-matter interaction experiments (>10$^{18}$ W/cm$^{2}$) with dense targets are highly sensitive to the effect of laser "noise" (in the form of pre-pulses) preceding the main ultra-intense pulse. These system-dependent…

Instrumentation and Detectors · Physics 2015-06-22 S. Feister , J. A. Nees , J. T. Morrison , K. D. Frische , C. Orban , E. A. Chowdhury , W. M. Roquemore

Propagation of high-intensity, high-contrast ($<10^{-8}$), 50\,fs laser pulses through triangilar copper capillaries is experimentally studied. The relative transmission through 20-mm-long, about 50\,$\mu$m wide capillaries is directly…

Plasma Physics · Physics 2015-04-03 V. E. Leshchenko , K. V. Gubin , V. I. Trunov , K. V. Lotov , E. V. Pestryakov

We predict collective 'free-space' lasing in a dense nanoscopic emitter arrangement where dipole-dipole coupled atomic emitters synchronize their emission and exhibit lasing behavior without the need for an optical resonator. At the example…

Quantum Physics · Physics 2025-09-26 Anna Bychek , Raphael Holzinger , Helmut Ritsch

We investigated the photoexcited carrier dynamics in Si by using optical pump and terahertz probe spectroscopy in an energy range between 2 meV and 25 meV. The formation dynamics of excitons from unbound e-h pairs was studied through the…

Materials Science · Physics 2015-05-27 Takeshi Suzuki , Ryo Shimano

Spectral diffusion is the phenomenon of random jumps in the emission wavelength of narrow lines. This phenomenon is a major hurdle for applications of solid state quantum emitters like quantum dots, molecules or diamond defect centers in an…