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Full-Text Articles in Optics

Slow Light With Interleaved P-N Junction To Enhance Performance Of Integrated Mach-Zehnder Silicon Modulators, Marco Passoni, Dario Gerace, Liam O'Faolain, Lucio Claudio Andreani May 2019

Slow Light With Interleaved P-N Junction To Enhance Performance Of Integrated Mach-Zehnder Silicon Modulators, Marco Passoni, Dario Gerace, Liam O'Faolain, Lucio Claudio Andreani

Cappa Publications

Slow light is a very important concept in nanophotonics, especially in the context of photonic crystals. In this work, we apply our previous design of band-edge slow light in silicon waveguide gratings [M. Passoni et al, Opt. Express 26, 8470 (2018)] to Mach-Zehnder modulators based on the plasma dispersion effect. The key idea is to employ an interleaved p-n junction with the same periodicity as the grating, in order to achieve optimal matching between the electromagnetic field profile and the depletion regions of the p-n junction. The resulting modulation efficiency is strongly improved as compared to common modulators based on …


Time-Resolved Electron (E,2E) Momentum Spectroscopy: Application To Laser-Driven Electron Population Transfer In Atoms, Hua-Chieh Shao, Anthony F. Starace Feb 2018

Time-Resolved Electron (E,2E) Momentum Spectroscopy: Application To Laser-Driven Electron Population Transfer In Atoms, Hua-Chieh Shao, Anthony F. Starace

Anthony F. Starace Publications

Owing to its ability to provide unique information on electron dynamics, time-resolved electron momentum spectroscopy (EMS) is used to study theoretically a laser-driven electronic motion in atoms. Specifically, a chirped laser pulse is used to adiabatically transfer the populations of lithium atoms from the ground state to the first excited state. During this process, impact ionization near the Bethe ridge by time-delayed ultrashort, high-energy electron pulses is used to image the instantaneous momentum density of this electronic population transfer. Simulations with 100 fs and 1 fs pulse durations demonstrate the capability of EMS to image the time-varying momentum density, including …


Distributions Of Long-Lived Radioactive Nuclei Provided By Star-Forming Environments, Marco Fatuzzo, Fred Adams Nov 2015

Distributions Of Long-Lived Radioactive Nuclei Provided By Star-Forming Environments, Marco Fatuzzo, Fred Adams

Faculty Scholarship

Radioactive nuclei play an important role in planetary evolution by providing an internal heat source, which affects planetary structure and helps facilitate plate tectonics. A minimum level of nuclear activity is thought to be necessary—but not sufficient—for planets to be habitable. Extending previous work that focused on short-lived nuclei, this paper considers the delivery of long-lived radioactive nuclei to circumstellar disks in star forming regions. Although the long-lived nuclear species are always present, their abundances can be enhanced through multiple mechanisms. Most stars form in embedded cluster environments, so that disks can be enriched directly by intercepting ejecta from supernovae …


Charged Particle Dynamics In The Magnetic Field Of A Long Straight Current-Carrying Wire, M. Fatuzzo, A. Prentice, T. Toepker Jan 2015

Charged Particle Dynamics In The Magnetic Field Of A Long Straight Current-Carrying Wire, M. Fatuzzo, A. Prentice, T. Toepker

Faculty Scholarship

The article discusses the concept behind motion of a charged particle in a non-uniform filed of a wire carrying current. Topics discussed include possible types of motion in a current carrying field, vector analysis of velocity and magnetic field of the particle and Coupled differential equations.


A Numerical Assessment Of Cosmic-Ray Energy Diffusion Through Turbulent Media, M. Fatuzzo, F. Melia Jan 2014

A Numerical Assessment Of Cosmic-Ray Energy Diffusion Through Turbulent Media, M. Fatuzzo, F. Melia

Faculty Scholarship

No abstract provided.


Effects Of Turbulence On Cosmic Ray Propagation In Protostars And Young Stars, M. Fatuzzo, F. C. Adams Jan 2014

Effects Of Turbulence On Cosmic Ray Propagation In Protostars And Young Stars, M. Fatuzzo, F. C. Adams

Faculty Scholarship

No abstract provided.


Assessing The Feasibility Of Cosmic-Ray Acceleration By Magnetic Turbulence At The Magnetic Center, M. Fatuzzo, F. Melia Jan 2012

Assessing The Feasibility Of Cosmic-Ray Acceleration By Magnetic Turbulence At The Magnetic Center, M. Fatuzzo, F. Melia

Faculty Scholarship

No abstract provided.


Quantitative Study Of Spin-Flip Co-Tunneling Transport In A Quantum Dot, S. Herbert, T-M. Liu, A. N. Ngo Jan 2012

Quantitative Study Of Spin-Flip Co-Tunneling Transport In A Quantum Dot, S. Herbert, T-M. Liu, A. N. Ngo

Faculty Scholarship

No abstract provided.