Childress, Lily. Visiting Professor

My research interests have included a variety of quantum optical phenomena in atomic and solid state physics, ranging from slowing and stopping light in atomic ensembles to studying electrons confined to a nanoscale region of a semiconductor. Most recently, I have become intrigued by experiments studying single electronic and nuclear spins in diamond. 

Using quantum-optical properties of a certain defect center in diamond, the nitrogen-acancy center, it is possible to prepare, manipulate, and measure single spins in a solid, in effect accomplishing single-spin ESR (electron spin resonance) or NMR (nuclear magnetic resonance).   I am building a table-top experiment to explore in greater detail how this system works, with the goal of improving the control we have over these spins to a level that may be relevant for applications in quantum information science or metrology.

In my spare time, I conduct significantly less sophisticated experiments on gravity, friction, pulley systems, knot theory, and other subjects relevant to roped ascent and descent of vertical surfaces. 

Lin, Hong. Professor

My research interests are laser physics, photorefractive optical devices, and nonlinear dynamics in optical systems. My research was focused on gas lasers and devices including photorefractive crystals till 2003. Since 2004, I have been studying a novel semiconductor laser: the vertical-cavity surface-emitting laser (VCSEL).

The VCSEL is a good candidate in many applications, e. g., optical data communications, highly integrated optics, and laser arrays. In applications, a small portion of the output beam may be reflected at the end of optical fiber or the surface of optical elements and re-enter the laser. This reflection is termed as optical feedback. Because the VCSEL is sensitive to optical feedback, it is interesting and useful to investigate effects of optical feedback on the VCSEL. My students and I have found that the spectral linewidth of the VCSEL can be significantly reduced by optical feedback. Under appropriate conditions, we can achieve single-mode operation when the solitary laser operates at multiple transverse modes.

Many students have participated in my research. They often continue their summer research for their senior theses. Most of them presented their results at regional or national professional meetings and became coauthors of my publications. My research is currently supported by the National Science Foundation.

When I am not busy at Bates or teaching Chinese to my children, Albert and Lily, I enjoy reading mystery novels and Chinese poetry.

Semon, Mark D. Professor

I've been the author or co-author on papers about quantum scattering theory, momentum and energy in the electromagnetic field, a formulation of quantum electrodynamics using the irreducible representations of SU(2), a new velocity space for special relativity, a new equation of state for a liquid-gas system near a critical point, and the dynamical interaction in the Aharonov Bohm effect. I also work with attorneys estimating the speeds of vehicles involved in fatal accidents. My hobbies include playing the banjo and guitar, farming in Montana, and restoring old pickup trucks.

Please see my WEBPAGE for more information about my interests in physics.

Smedley, John E. Professor

My primary research interests lie in atomic collisions. My students and I use lasers to excite atoms and detect time- and wavelength-resolved atomic emission to measure collision rates and radiative lifetimes. Most recently I've been working on projects involving collision-induced absorption in a barium metal/rare gas vapor, and collisions of rare gases with barium atoms in the 5d7p 3D1 fine-structure state.

Wollman, Eric R. Professor

My research interests are in astrophysics and cosmology, specifically the nature of dark matter and conditions in the early universe. I teach a variety of physics courses at all levels.   

I also enjoy teaching introductory astronomy courses appropriate for students majoring in the social sciences and humanities. Two such courses that I teach regularly are Astronomy 101 - The Milky Way Galaxy and Astronomy 104 - Cosmology in the Twentieth Century. I have a lot of fun with the First-Year Seminar FYS 340 - Planetarium Production, in which students conceive, write, produce, and present shows in the College’s Ladd Planetarium. I enjoy all sorts of music, and I am a cellist in the College orchestra. I am currently Chair of the Department.

Ruff, George A Charles A. Dana Professor
786-6322, Carnegie Science Hall, Room 330
gruff@bates.edu

My students and I study the forces light exerts on atoms. We build novel lasers and "magneto-optical atom traps", using the pressure of light to suspend clouds of atoms in vacuum. Recently, we succeeded in trapping two different kinds of atoms (Rb and Cs) simultaneously, allowing us to study interactions between two clouds of ultracold atoms.

Please see my HOMEPAGE for more information.