Guiding of Rydberg atoms in a high-gradient magnetic guide

We study the guiding of $^{87}$Rb 59D$_{5/2}$ Rydberg atoms in a linear, high-gradient, two-wire magnetic guide. Time delayed microwave ionization and ion detection are used to probe the Rydberg atom motion. We observe guiding of Rydberg atoms over a period of 5 ms following excitation. The decay time of the guided atom signal is about five times that of the initial state. We attribute the lifetime increase to an initial phase of $l$-changing collisions and thermally induced Rydberg-Rydberg transitions. Detailed simulations of Rydberg atom guiding reproduce most experimental observations and offer insight into the internal-state evolution

Microscopic Theory of Spontaneous Decay in a Dielectric

The local field correction to the spontanous dacay rate of an impurity source atom imbedded in a disordered dielectric is calculated to second order in the dielectric density. The result is found to differ from predictions associated with both "virtual" and "real" cavity models of this decay process. However, if the contributions from two dielectric atoms at the same position are included, the virtual cavity result is reproduced.Comment: 12 Page

Mechano-chemical synthesis and analysis of zinc and pyrogallol [4] arene complex under solvent-free and ambient conditions [abstract]

Faculty Mentor: Dr Jerry L. Atwood, ChemistryAbstract only availableHerein, we report a solvent-free approach for chemical synthesis which focuses on mechanochemically forming products from reactants under ambient conditions. With this protocol, several organo-metallic complexes or frameworks of zinc and pyrogallol[4]arenes were synthesized and analyzed with MALDI-TOF mass spectrometry combined with solid state carbon thirteen Nuclear Magnetic Resonance (13CNMR). This synthetic approach is in line with the synthetic methodology of green chemistry which focuses on eco-friendly chemical synthesis or synthetic routs

A personal journey of change: 20 years introducing technology inside and outside of the Organic Chemistry classroom.

Lectures lacking in student engagement have been shown to be largely ineffective with respect to learning and knowledge retention (Halloun, 1985) particularly with conceptually difficult courses such as organic Chemistry. Deeper learning and critical thinking skills are gained through active participation inside and outside of the classroom ( Crouch & Mazur, 2001; Flynn, 2015; Prince, 2004; Wieman et al., 2014). My first realization that there had to be a better way than passive lecture came in 1997. Students blindly copied reactions and mechanisms off the blackboard without comprehending. I wrote at such a fast pace, covering multiple black boards that sometimes students had not finished copying what I had written by the time I started erasing the first board. My first solution was to create course notes with blanks so that we could work on questions together. However, with increasing accessibility and affordability of digital devices the way people learn and expect to be taught has fundamentally changed. Thus, I gradually shifted to online assignments, in-class student response systems and online course material to facilitate flipping the classroom. The next step in my journey in utilizing technology for promoting student success and engagement was the development and use of an interactive online textbook with weekly reading assignments. We will discuss the gradual and then accelerated introduction of technology into and outside of the classroom. We will share student perceptions of the various course elements based on survey responses, the impact these changes have had on student success and discuss the changing expectations of students. Crouch & Mazur (2001). Am. J. Phys., 69, 970–977. Flynn (2015). Chem. Educ. Res. Pract., 16, 198-211. Halloun (1985). Am. J. Phys., 53, 1043–1048. Prince (2004). J. Eng. Educ., 93, 223–23. Wieman et al. (2014). The Physics Teacher, 52, 51-53

Spatial Control of Photoemitted Electron Beams using a Micro-Lens-Array Transverse-Shaping Technique

A common issue encountered in photoemission electron sources used in electron accelerators is the transverse inhomogeneity of the laser distribution resulting from the laser-amplification process and often use of frequency up conversion in nonlinear crystals. A inhomogeneous laser distribution on the photocathode produces charged beams with lower beam quality. In this paper, we explore the possible use of microlens arrays (fly-eye light condensers) to dramatically improve the transverse uniformity of the drive laser pulse on UV photocathodes. We also demonstrate the use of such microlens arrays to generate transversely-modulated electron beams and present a possible application to diagnose the properties of a magnetized beam.Comment: arXiv admin note: text overlap with arXiv:1609.0166

A molecular theory for two-photon and three-photon fluorescence polarization

In the analysis of molecular structure and local order in heterogeneous samples, multiphoton excitation of fluorescence affords chemically specific information and high-resolution imaging. This report presents the results of an investigation that secures a detailed theoretical representation of the fluorescence polarization produced by one-, two-, and three-photon excitations, with orientational averaging procedures being deployed to deliver the fully disordered limits. The equations determining multiphoton fluorescence response prove to be expressible in a relatively simple, generic form, and graphs exhibit the functional form of the multiphoton fluorescence polarization. Amongst other features, the results lead to the identification of a condition under which the fluorescence produced through the concerted absorption of any number of photons becomes completely unpolarized. It is also shown that the angular variation of fluorescence intensities is reliable indicator of orientational disorder

Antenna pattern shaping, sensing, and steering study Final report

Design of steerable satellite antenna with beam pattern sensing syste

Generation of Relativistic Electron Bunches with Arbitrary Current Distribution via Transverse-to-Longitudinal Phase Space Exchange

We propose a general method for tailoring the current distribution of relativistic electron bunches. The technique relies on a recently proposed method to exchange the longitudinal phase space emittance with one of the transverse emittances. The method consists of transversely shaping the bunch and then converting its transverse profile into a current profile via a transverse-to-longitudinal phase-space-exchange beamline. We show that it is possible to tailor the current profile to follow, in principle, any desired distributions. We demonstrate, via computer simulations, the application of the method to generate trains of microbunches with tunable spacing and linearly-ramped current profiles. We also briefly explore potential applications of the technique.Comment: 13 pages, 17 figure