A Fully Tunable Microcavity

Date: 
February 8, 2010 (All day)
Speaker: 
Dr. Russell Barbour

Semiconductor optical microcavities that combine high Q-factors with a small mode volume play a vital role in modifying the interaction between light and matter. Several interesting phenomenon arise when an emitter is introduced into such a cavity. These include enhancement or suppression of the spontaneous emission rate (weak coupling) and normal mode splitting (strong coupling).

Towards Atomic-Scale Optical Probes

Date: 
May 24, 2010 (All day)
Speaker: 
Dr. Jeffrey Guest

Over the past two decades, ultra-high vacuum (UHV) scanning tunneling microscopy (STM) and single particle laser spectroscopy have made great strides in measuring and controlling nanoscale and atomic-scale systems incomplementary ways.

Optofluidic ring resonator technology platform for rapid and sensitive biological and chemical sensing

Date: 
February 10, 2009 (All day)
Speaker: 
Dr. Xudong Fan

The optical ring resonator is an emerging sensing technology that has recently been under intensive investigation. In a ring resonator, light propagates in the form of whispering gallery modes (WGMs), which results in a light-analyte interaction length much longer than the resonator physical size. Consequently, the ring resonator can achieve a much improved detection limit, lower sample volume, and larger integration density than the traditional waveguide or optical fiber based sensor.

Towards table-top free-electron lasers (FELs) using laser-accelerated electron beams

Date: 
May 28, 2009 (All day)
Speaker: 
Matthias Fuchs

Laser-plasma accelerators can accelerate electrons to relativistic energies over distances three orders of magnitude smaller than required by conventional accelerators. Recent breakthroughs have led to stable, quasi-monoenergetic electron beams in the gigaelectronvolt-scale from few-centimeter accelerator lengths. Owing to their unprecedented features, such as intrinsically ultrashort pulse durations and expected low emittances, these electron beams are perfectly suited for driving a next generation of X-ray light sources.

Observation of quantum diffractive collisions using shallow atomictraps

Date: 
May 11, 2009 (All day)
Speaker: 
Dr. Kirk Madison

We discuss measurements and calculations of the trap loss rate for laser cooled 87Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap when exposed to a room temperature background gas of Ar. We study the loss rate as a function of trap depth and find that copious glancing collisions, which occur in the so-called quantum-diffractive regime and impart very little energy to the trapped atoms, result in significant differences in the loss rate for the MOT compared to a pure magnetic trap due solely to the difference in potential depth.

Realistic quantum-enhanced interferometry

Date: 
July 28, 2009 (All day)
Speaker: 
Dr. Konrad Banaszek

It is widely recognized that the use of nonclassical states of light allows one to overcome the shot-noise limit in precision measurements. The enhancement comes from exploiting inherently quantum features, such as entanglement, that are sensitive to decoherence. The outstanding challenge is to design quantum-enhanced measurement schemes that remain robust in realistic environments. We review our recent work in this direction for optical interferometry.

Ultrafast vibrational spectroscopy of photochemistry and anharmonic coupling

Date: 
April 13, 2009 (All day)
Speaker: 
Dr. David McCamant

Research in the McCamant lab focuses on ultrafast nuclear dynamics in photochemistry and photobiology, with the hope that we can illuminate how excited-state structure and vibrational energy flow are related to photochemical function. Our work is conducted talong two integrated themes: (1) ultrafast electronic and vibrational studies of photochemical reaction dynamics of DNA and (2) development of new spectroscopic techniques to study vibrational coupling.

Single Spins in Diamond for Quantum Networks and Magnetic Sensing

Date: 
March 9, 2009 (All day)
Speaker: 
Gurudev Dutt

I will discuss experiments that demonstrate addressing, preparation, and coherent control of coupled electronic and nuclear spin qubits in the diamond lattice at room temperature [1,2]. 

Optimal quantum memory with atomic ensembles

Date: 
February 23, 2009 (All day)
Speaker: 
Dr. Irina Novikova

Efficient and reliable quantum communication will require the control of individual photons. As a step toward this objective, wehave demonstrated promising techniques that involve using a dynamic form of electromagnetically induced transparency to optimally and
reversibly map arbitrary pulses of light onto an ensemble of warm Rubidium atoms. Our techniques, demonstrated in atomic vapor, are
applicable to a wide range of systems and protocols.

Imaging spin injection and transport in semiconductor 'spintronic" devices

Date: 
February 2, 2009 (All day)
Speaker: 
Dr.Scott Crooker

Three essential elements of a semiconductor spin transport device are i) an efficient mechanism for electrically injecting spin-polarized electrons into a semiconductor, ii) a practical means for spinmanipulation and transport, and iii) a simple electronic scheme for detecting the resulting spin polarization. This talk will address each of these three elements in turn using data from low-temperature, magneto-optical scanning Kerr microscopy studies.

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