Quantum Lunch Location:
T-Division Conference Room, TA-3,
Building 123, Room 121
Quantum Institute: Visitor Schedule
The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.
Thursday, July 15, 2009
12:30 PM - 2:00 PM
Speaker: Douglas Bradshaw, CCS-3
Title: Tricks with Slowed, Stopped, and Fast Light
The group velocity is the speed with which a pulse of light travels through a medium. Using nonlinear optics, it is possible to alter the group velocity of light in a medium without significantly altering either the phase velocity or the absorption of that light. These changes can be huge--pulses can be slowed to pedestrian speeds, stopped, given infinite speed, or made to travel backward.
We begin this talk by discussing the basic effects of the group velocity on the energy and momentum associated with the pulse. We then introduce a powerful and simple generalization of Snell's Law and use it to show how real time changes in the group velocity my be used to scale a pulse bandwidth over many orders of magnitude. Finally, we show how it should be possible, through the manipulation of the group index, to simulate a 1 km optical cavity on a 100 micron chip, and how one might create optical cavities with effective vanishing and even negative effective path lengths. Physical effects expected to occur in such cavities include controlled and enhanced spontaneous emission (in the case of a vanishing-length cavity) and a negative Doppler shift (in the case of a negative-length cavity).