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This page contains an archive of all entries posted to Physics Announcements in the General Announcements category. They are listed from newest to oldest.

Employment Opportunities is the previous category.

Notable Achievements is the next category.

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General Announcements

November 25, 2013

PhD Proposal - Jane Sprigg

Date: Monday, November 25, 2013
Time: 12:30 pm
Location: PHYS 401

TITLE:
New measurement scheme for second-order correlation measurements of thermal light

ABSTRACT:
Experiments using second order correlations have proven to be important for many applications, such as the Hanbury Brown Twiss interferometer which measures the angular size of stars, three dimensional LIDAR imaging, ghost imaging, quantum computing, and lithography. Of these experiments, only one regularly uses thermal light: the Hanbury Brown Twiss interferometer. The other experiments usually use lasers or entangled light sources, which are less than practical for many real-world applications. In addition, entangled experiments are typically performed at the single photon level and prone to decoherence. However, all of these experiments can also be performed with thermal light, such as sunlight, if one condition is met: the temporal coherence is increased allowing many measurements to be made within the coherence time. This is problematic for thermal light, as its temporal coherence is the inverse of its bandwidth, on the order of 10^-15. Our goal is to investigate the use of linear and nonlinear optics to stretch the time-scale of thermal light, reducing the bandwidth and increasing the temporal coherence without drastically reducing the intensity, allowing Hui Chen's Positive Negative Fluctuation Correlation Protocol to be used. This would result in a new method to achieve high intensity, high contrast second-order correlation measurements with broadband thermal light.

November 11, 2013

PhD Proposal - Alex Henegar

Date: Monday, November 11, 2013
Time: 2:00 pm
Location: PHYS 401

TITLE:
Investigation of Atomic Layer Deposition of Metal Oxides on III-V Semiconductors

ABSTRACT:
Atomic layer deposition (ALD) is becoming a leading technique for the fabrication of nanoscale materials because of its precise thickness control and unprecedented capability of film uniformity and surface conformality. Applications for such materials are diverse, ranging from Li-ion batteries and dye-sensitized solar cells to coatings on 3D structures and replacing SiO2 with high dielectric constant materials in metal oxide semiconductor field effect transistors (MOSFETs).

Our current understanding of ALD is based on ideal, one-pathway mechanisms. However, recent studies have shown we know very little about what reactions actually take place during ALD. The purpose of this research is to widen our understanding of the fundamentals of ALD by characterizing specific ALD processes such as the deposition Ta2O5 on InAs(100), post-deposition annealing effects on TiO2 thin films, the diffusion phenomenon of III-V semiconductor substrate atoms through metal oxide overlayers and explore the diffusion barrier capabilities of Al2O3 in these thin film systems.


September 10, 2013

PhD Proposal - Dan Jones

Date: Monday, September 23, 2013
Time: 1:00 pm
Location: PHYS 401

Title
"Nonlinear Phase Shifts at Single-Photon Power Levels Using Tapered Optical Fibers in Rubidium Vapor"

Title
Our group has recently proposed a new form of macroscopic “phase-entangled” coherent state pulses with the potential to radically improve Quantum Communications (QC) systems. In contrast to conventional entangled pairs of single-photons which are highly susceptible to loss, these entangled pulses contain large numbers of photons and are predicted to propagate over long distances through lossy fiber channels. The key experimental requirement for generating these new entangled states is the realization of ultra-low power nonlinear phase shifts. Roughly speaking, what is needed is a robust Kerr-type nonlinearity in which the presence of a single-photon imparts a sizable phase shift on a macroscopic coherent state pulse.

Here I propose to experimentally demonstrate this nonlinear single-photon phase shift using a system comprised of a sub-wavelength diameter Tapered Optical Fiber (TOF) suspended in atomic rubidium (Rb) vapor. The proposed work leverages our group’s recent experience and experimental infrastructure in using the “TOF in Rb” system to demonstrate ultra-low power two-photon absorption. A successful demonstration of the proposed single-photon phase shifts would represent a significant advance in quantum optics, with a number of follow-on applications in QC.


August 12, 2013

PhD Defense - Patricia Sawamura

You're invited to attend Patricia's dissertation defense.

Date: Monday, August 12, 2013
Time: 10:00 am
Location: PHYS 401

TITLE:
Retrieval of optical and microphysical properties of aerosols from a hybrid lidar dataset

ABSTRACT:
Over the past decade the development of inversion techniques for the retrievals of aerosol microphysical properties (e.g. effective radius, volume and surface-area concentrations) and aerosol optical properties (e.g. complex index of refraction and single scattering albedo) from multiwavelength lidar system brought a new perspective in the study of the vertical distribution of aerosols. In this study retrievals of such parameters were obtained from a hybrid multiwavelength lidar dataset for the first time. In July of 2011, in the Baltimore-Washington DC region, synergistic profiling of optical and microphysical properties of aerosols with both airborne in-situ and ground-based remote sensing systems was performed during the first deployment of DISCOVER-AQ. The hybrid multiwavelength lidar dataset combines elastic ground-based measurements at 355 nm with airborne High Spectral Resolution Lidar (HSRL) measurements at 532 nm and elastic measurements at 1064 nm that were obtained up to 5 km apart of each other. This was the first study in which optical and microphysical retrievals from lidar were obtained during the day and directly compared to AERONET and in-situ measurements. Good agreement was observed between lidar and AERONET retrievals. Larger discrepancies were observed between lidar retrievals and in-situ measurements obtained by the aircraft and aerosol hydration processes that were not taken into account in the study are believed to be the cause for the discrepancies observed.

July 12, 2012

Welcome Dr. Jason Kestner!

Jason KestnerThe Department welcomes its newest member, Assistant Professor, Dr. Jason Kestner.

Dr. Kestner says of his research:
"Broadly speaking, I am interested in engineering useful physical devices that exploit the strange (but beautiful!) features of quantum mechanics. I am pursuing that interest via theoretical studies of ultracold atoms, ultracold polar molecules, and "artificial" atoms and molecules, i.e., quantum dot systems in solid state materials. My research on ultracold systems is motivated primarily by the prospect of building a versatile quantum simulator, while my research on quantum dots is motivated primarily by the prospect of quantum information processing with semiconductor spin qubits. In addition to these, I am always excited by opportunities to explore new applications of uniquely quantum behavior."

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