Date: Monday, September 23, 2013
Time: 1:00 pm
Location: PHYS 401
"Nonlinear Phase Shifts at Single-Photon Power Levels Using Tapered Optical Fibers in Rubidium Vapor"
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.