Created photon distribution in a cavity with a moving wall

弘樹 斎藤, Hiroki Saito

Ihar Babushkin, Oliver Melchert, Uwe Morgner +1 more

We consider photon trapping by refractive index steps moving with speed of light. We show that such trapping fundamentally differs from conventional, ”standing” cavities, demonstrating zero reflection through the walls and breaking several fundamental limits.

Lazo M. Manojlović

In this paper a general theoretical analysis of the average photon path length between two consecutive photon reflections from the cavity walls has been presented. The presented analysis relies only on the energy conservation law and the assumption of the uniform photon distribution within the cavity volume. The obtained general result coincides with the solution previously obtained but under more stringent conditions.

A. B. Klimov, V Altuzar

Edward A. Hinds, K. S. Lai, M. Schnell

Over the past ten years, our group has investigated the effects of confinement on atoms inside metallic micron–sized cavities in order to elucidate some basic phenomena in the field of cavity quantum electrodynamics (QED). The first of these was the inhibition of spontaneous emission from an atom inside a cavity. This was followed by a laser spectroscopic measurement of the van der Waals interaction between a single Rydberg atom and a gold cavity, which showed that a simple electrostatic model of the atom–cavity interaction is correct when the cavity is small enough. More recently, the retarded Casimir–Polder force was measured between a ground state sodium atom and a large cavity, demonstrating that the van der Waals potential fails at long enough range and that the vacuum fluctuations of the field then have an important role in the interaction of the atom with the cavity. Our group is now pushing forward these investigations to study cavities whose walls have losses and dispersion, where the theory of cavity QED is significantly more complicated. With real surfaces, we have to deal with the complex dielectric response ε(ω) of the material, which exhibits frequency–dependent absorption and dispersion. One particularly interesting case is when a downward transition in the atom is resonant with an excitation of the cavity walls. This opens a new branch for the atomic decay: as an alternative to creating a photon within the space surrounded by the cavity walls the atomic decay can now create an electromagnetic excitation of the walls themselves. Another novel feature of our experiments is that the Bohr frequencies of the atom are close to the kT/h, where T is room temperature. We therefore expect to be able to measure effects associated with QED at finite temperature; in other words, to study how the blackbody radiation affects our experiments. By conducting experiments with real surfaces, we hope to elucidate and perhaps simplify the theoretical models used to describe these systems.

Shengwang Du, Chang Liu, Yuan Sun +3 more