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Articles 1 - 5 of 5
Full-Text Articles in Physics
Optical Metasurfaces, Fatih Balli
Optical Metasurfaces, Fatih Balli
Theses and Dissertations--Physics and Astronomy
Traditional optical elements, such as refractive lenses, mirrors, phase plates and polarizers have been used for various purposes such as imaging systems, lithographic printing, astronomical observations and display technology. Despite their long-term achievements, they can be bulky and not suitable for miniaturization. On the other hand, recent nanotechnology advances allowed us to manufacture micro and nanoscale devices with ultra-compact sizes. Metasurfaces, 2D engineered artificial interfaces, have emerged as candidates to replace traditional refractive lenses with ultra-thin miniaturized optical elements. They possess sub-wavelength unit cell structures with a specific geometry and material selection. Each unit cell can uniquely tailor the phase, …
Perturbative Generalization Of Nonparaxial Ultrashort Tightly-Focused Elegant Laguerre-Gaussian Beams, Andrew M. Vikartofsky
Perturbative Generalization Of Nonparaxial Ultrashort Tightly-Focused Elegant Laguerre-Gaussian Beams, Andrew M. Vikartofsky
Department of Physics and Astronomy: Dissertations, Theses, and Student Research
An analytical method for calculating the electromagnetic fields of a nonparaxial elegant Laguerre-Gaussian (eLG) vortex beam is presented for arbitrary pulse duration, spot size, and LG mode. This perturbative approach provides a numerically tractable model for the calculation of arbitrarily high radial and azimuthal LG modes in the nonparaxial regime, without requiring integral representations of the fields. A key feature of this perturbative model is its use of a Poisson-like frequency spectrum, which allows for the proper description of pulses of arbitrarily short duration. The time-domain representation of this model is presented as a non-recursive closed-form expression to any order …
Magneto-Optical Properties Of Thin Permalloy Films: A Study Of The Magneto-Optical Generation Of Light Carrying Angular Momentum, Patrick D. Montgomery
Magneto-Optical Properties Of Thin Permalloy Films: A Study Of The Magneto-Optical Generation Of Light Carrying Angular Momentum, Patrick D. Montgomery
Theses and Dissertations--Electrical and Computer Engineering
Magneto-optical materials such as permalloy can be used to create artificial spin- ice (ASI) lattices with antiferromagnetic ordering. Magneto-optical materials used to create diffraction lattices are known to exhibit magnetic scattering at the half- order Bragg peak while in the ground state. The significant drawbacks of studying the magneto-optical generation of OAM using x-rays are cost, time, and access to proper equipment. In this work, it is shown that the possibility of studying OAM and magneto-optical materials in the spectrum of visible light at or around 2 eV is viable. Using spectroscopic ellipsometry it is possible to detect a change …
Self-Energy Correction To The Hyperfine Splitting For Excited States, Benedikt J. Wundt, Ulrich D. Jentschura
Self-Energy Correction To The Hyperfine Splitting For Excited States, Benedikt J. Wundt, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The self-energy corrections to the hyperfine splitting is evaluated for higher excited states in hydrogenlike ions using an expansion in the binding parameter Zα, where Z is the nuclear-charge number and α is the fine-structure constant. We present analytic results for D, F, and G states, and for a number of highly excited Rydberg states, with principal quantum numbers in the range 13≤n≤16, and orbital angular momenta =n-2 and =n-1. A closed-form analytic expression is derived for the contribution of high-energy photons, valid for any state with ≥2 and arbitrary n, , and total angular momentum j. The low-energy contributions …
Generation Of High-Energy Photons With Large Orbital Angular Momentum By Compton Backscattering, Ulrich D. Jentschura, Valery G. Serbo
Generation Of High-Energy Photons With Large Orbital Angular Momentum By Compton Backscattering, Ulrich D. Jentschura, Valery G. Serbo
Physics Faculty Research & Creative Works
Usually, photons are described by plane waves with a definite 4-momentum. In addition to plane-wave photons, "twisted photons" have recently entered the field of modern laser optics; these are coherent superpositions of plane waves with a defined projection ℏm of the orbital angular momentum onto the propagation axis, where m is an integer. In this Letter, we show that it is possible to produce high-energy twisted photons by Compton backscattering of twisted laser photons off ultrarelativistic electrons. Such photons may be of interest for experiments related to the excitation and disintegration of atoms and nuclei, and for studying the …