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About May 2010

This page contains all entries posted to Physics Announcements in May 2010. They are listed from oldest to newest.

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May 2010 Archives

May 5, 2010

Seminar: Wednesday, May 5, 2010 at 3:30 pm

The Invention and 50th Anniversary of the Laser
Sheng Liu
UMBC
2010 is recognized as the 50th anniversary of laser after its first demonstration in 1960 by Theodore Maiman at Hughes Research Lab. From DVD players to eye surgery, the laser is one of the greatest inventions of the 20th century—one that has revolutionized the way we live.

The laser was not discovered from a single breakthrough by one individual, but from a series of developments incorporating hundreds of great minds’ efforts, starting from Albert Einstein’s paper of “On the quantum theory of radiation” in 1917. Then Richard Tolman, Rudolf Ladenburg, and V.A Fabrikant brought up the ideas of negative absorption, stimulated emission, and population inversion, respectively. However, population inversion was never achieved experimentally until 1954 when Charles H. Townes and James P. Gordon made the first MASER (Microwave Amplification by Stimulated Emission of Radiation). Immediately after that, scientists started wondering how to make a MASER working at optical frequencies.

Starting from 1957, the competition of inventing an optical MASER began heating up. Teams at half a dozen laboratories set out, each hoping to be the first to succeed. The term “laser” was first introduced to the public in Gordon Gould’s 1959 conference paper. In 1960, Theodore Maiman was the first one to a demonstrate laser in ruby, which by the way was considered as a dark horse in this laser race. Over the next 30 years, Gordon Gould fought with the United States Patent and Trademark Office to obtain patents for the laser and related technologies, and was finally issued forty-eight patents, with optical pumping, collisional pumping, and applications patents being the most important.

The competition of developing new types of lasers did not end there. A brief review of important laser breakthroughs over the last 50 years will be presented.

May 17, 2010

PhD Proposal Defense - Meimei Lai

Meimei successfully defended her PhD proposal on Monday, May 17, 2010.

TITLE:
Quantum Information Processing with Tapered Optical Fibers

ABSTRACT:
The race between various approaches (ions, NMR, photons, etc.) to quantum computing has been becoming more and more fierce since the idea of quantum computer came up in the early 1980’s. The research on the quantum information processing is not only providing us with the possibility of a revolutionary computer which can do several important things (quantum simulation, large number factorization and database searching) that are difficult or impossible on a traditional computer, but also giving us profound understanding and new insights about nature.

Our group has been interested in an optical approach to quantum computation and proposed a universal optical quantum logic gate that uses the quantum Zeno effect to prevent errors associated with two photons exiting a device in one mode. These “Zeno Gates” require very strong Two-Photon Absorption (TPA) but very weak single photon absorption (SPA). In addition to Zeno Gates, strong TPA can be also used to realize ultra efficient classical optical switches, and it is a promising tool to develop a new kind of single photon source.

My PhD research will primarily focus on the experimental realization of strong TPA with weak light beams. The system we will be using consists of a sub-wavelength diameter Tapered Optical Fiber (TOF) suspended in Rubidium vapor. Once achieved, this strong TPA system will also allow us to investigate a number of other effects in quantum optics and quantum information processing. Recent experimental progresses on the development of a state of the art TOF fabrication system and future plans will be discussed.

PhD Proposal Defense - Paul Corbitt

Paul successfully defended his PhD proposal on Monday, May 17, 2010.

TITLE:
Applying Nuclear Decay Models to Schizophrenia

ABSTRACT:
Schizophrenia is a crippling mental illness that disables schizophrenics for life. This disability is a burden shared by those affected and society. Research has not identified a definitive cause of schizophrenia, rather a patchwork of hypotheses have been advanced. A novel model that is isomorphic to the model governing radioactive decays sheds new light on schizophrenia.

A rich variety of epidemiological data is available to model. The model’s parameters have specific physical meaning, which serve as a guiding principle in searching for the causes of schizophrenia. This model will challenge the conventional wisdom about schizophrenia and explain various features of schizophrenia epidemiology. Preliminary results show a majority of the population is immune to schizophrenia. The model points towards the physical processes associated with the etiology of schizophrenia.

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