Coherent Excitation of Optical Spectra of Atoms Passing Through a Crystal

Владилен Владимирович Окороков, D.L. Tolchenkov, I. S. Khizhnyakov +4 more

H. Kalt, Claus F. Klingshirn

Yoichi Nakai, Yuji Nakano, T. Azuma +6 more

We report the Autler-Townes doublet demonstrating a novel type of coherent interaction of atoms not with photons but with a periodic crystal field when the atom is in flight through a crystal at high velocity. It was observed by the nonoptical X-VUV (vacuum-ultraviolet) double resonance of three-dimensional resonant coherent excitation with good coherence. The states strongly coupled in the VUV region were probed by the excitation in the x-ray region. The characteristic spectra are well interpreted by an analogy of the dressed atom concept often adopted for the atom-photon interaction.

Constantine Mavroyannis

The theory of the coherent pairing of excitons in the presence of a resonant electromagnetic field is generalized to describe the biexciton spectra of molecular crystals, which contain several molecules (atoms) in the unit cell. The excitation spectrum for crystals like anthracene having two molecules per unit cell is discussed in detail. It is found that, at high exciton densities and under resonance of near-resonance conditions and at temperatures below some value T c , the formation of four biexciton states is feasible provided that the dielectric gaps induced by the electromagnetic field are less than those of the corresponding biexciton states. Expressions for the absorption coefficient describing optical transitions to the biexciton states are derived.

Владилен Владимирович Окороков

Lucas Peng

Integrating atomic physics with nanophotonics devices provides a new research platform for quantum optics and many-body physics. The robustness and scalability of advanced lithographic fabrication technology provide powerful tools to enhance and control atom-photon interaction. Dispersion engineered photonic crystal waveguides (PCWs), such as the alligator photonic crystal waveguides (APCWs) described in this thesis, allow stable trapping and probing of atoms via guided modes (GMs). By tuning the photonic band-edges of the PCWs, the photon-mediated interactions between atoms can be modified. This thesis describes simulations and experiments that develop a quantitative understanding of atomic motion near the surfaces of APCWs. The atoms are delivered to APCWs using optical lattice. Synchronous with the moving lattice, transmission spectra for a guided-mode probe field are recorded as functions of lattice transport time and frequency detuning of the probe beam. With these 2D "clocked" spectra, we have been able to validate quantitatively our numerical simulations, which are based upon a detailed understanding of atomic trajectories that pass around and through nanoscopic regions of the APCW under the influence of optical and surface forces. By introducing auxiliary GMs of various polarizations and intensities, we have begun to control the atomic trajectories to some degree. For example, atoms can be guided to the central vacuum gap of the APCW at predetermined times and with known AC-Stark shifts. The applications of combining clocked atom delivery and numerical simulation include enabling high fractional filling of optical trap sites within PCWs, calibration of optical fields within PCWs, and utilization of the time-dependent, optically dense atomic medium for novel nonlinear optical experiments.