We have studied the concentration dependent fluorescence decay kinetics of ceramic Nd:YAG, to resolve inconsistencies in the previous literature. Our data indicate that earlier reports of single exponential lifetimes even at Nd concentrations of a few percent were due to the effects of long-pulse excitation. Under short-pulse excitation the fluorescence decay is nonexponential for concentration...

We present a complete theoretical description of atomic storage states in the multimode framework by including spatial coherence in atomic collective operators and atomic storage states. We show that atomic storage states are Dicke states with the maximum cooperation number. In some limits, a set of multimode atomic storage states has been established in correspondence with multimode Fock state...

Horizontal transfer of nucleic acid sequences is a widespread process of genetic change in bacterial populations, one taking on a variety of specific forms. A model capturing some of the general features of this process is formulated. Two major subsidiary variants of this model are analyzed. The first lacks competition between cells. In this case, the transferred genetic element can approach fi...

We use an optically dense anisotropic magneto-optical trap to study recoil-induced resonances RIRs in the transient high-gain regime. We find that two distinct mechanisms govern the atomic dynamics: the finite, frequency-dependent atomic response time and momentum-space population redistribution. At low input probe intensities, the residual Doppler width of the atoms, combined with the finite a...

This paper addresses the modelling issue of the second solar spectrum. This is the name given to the linearly polarized spectrum which can be observed close to the solar limb using spectro-polarimeters of high polarimetric sensitivity (Stenflo and Keller, 1997). The second solar spectrum is due to scattering processes and offers a rich diagnostic potential for exploring solar magnetic fields vi...

Accurate knowledge of the rate as well as the mechanism of excitation of the bending mode of CO2 is necessary for reliable modeling of the mesosphere–lower thermosphere (MLT) region of the atmosphere. Assuming the excitation mechanism to be thermal collisions with atomic oxygen, the rate coefficient derived from the observed 15 μm emission by space-based experiments (kATM = 6.0× 10 cms) differs...