Negative refraction and photonic-crystal optics in cold atomic gases

Peter P. Orth

Ai‐Xia Zhang, Ju-Kui Xue

Zach J. Simmons

Marina Litinskaya, Evgeny A. Shapiro

We describe propagation of light in a gas with periodic density modulation, demonstrating photonic-crystal-like refraction with negative refraction angles. We address the role of poorly defined boundaries and damping and derive an optical analog of the quantum adiabatic theorem. For Cs atoms in an optical lattice, we show that relying on semiadiabatic propagation one can excite and spatially split positively and negatively refracting modes at experimentally available gas densities.

Deniz D. Yavuz, N. R. Brewer, Zachary Noel Buckholtz +1 more

Abstract : In this project, our long-term goal is to demonstrate the first negative refraction in atomic systems. Although the concept of negative refraction remained an academic curiosity for a long time, it is now well-understood that negative refraction may have important and far-reaching practical implications. The key challenge in observing negative refraction in the optical region of the spectrum is the weakness of the magnetic response. Our central experimental result during this project has been the first observation of Rabi flopping of a magnetic dipole transition in the optical region of the spectrum. We have performed this experiment using the 7F0-5D1 transition of europium ions in a cryogenically cooled doped crystal. This is a major result; we have shown for the firs time that an electron can interact sufficiently strongly with the magnetic field of a light wave and coherently move between the levels. Another important result during this project was the proposal for a new type of materials that exhibit negative refraction. Because of these achievements, observing negative refraction and left-handed electromagnetic waves in atomic systems seem within reach for the first time.

James A. McKelvie