A Fokker-Planck equation is derived for the energy distribution of atoms in a three-dimensional harmonic trap with fluctuations in the spring constant and the equilibrium position. Using this model, we predict trap lifetimes based on the measurable noise spectra of the fluctuations. The energy distributions evolve into a single eigenmode where the apparent temperature of the distribution remain...

The frequency dependence of the imaginary part of the infrared conductivity is calculated for a superconductor. Sharp structure, characteristic of superconductivity with an order parameter with s-wave symmetry, appears in the BCS limit as a minimum at a frequency equal to twice the gap value. This structure scales with temperature but gets progressively smeared and shifted as impurity scatterin...

Adaptive finite elements are the method of choice for accurate simulations of optical components. However as shown recently by Bienstman et al. many finite element mode solvers fail to compute the propagation constant’s imaginary part of a leaky waveguide with sufficient accuracy. In this paper we show that with a special goal oriented error estimator for capturing radiation losses this problem...

We propose and analyze a new type of optical amplifier that is formed by addition of gain in the periodic cladding of a transverse Bragg resonance waveguide [Opt. Lett. 27, 936 (2002)]. Using the coupled-wave formalism, we calculate the mode profiles, the exponential gain constant, and, for comparison, the gain enhancement compared with those of conventional semiconductor optical amplifiers. In...

Threshold (or relative magnitude) search is traditionally performed iteratively in a bit-serial manner in optical database/knowledge-base machines which results in an execution time proportional to the operand size. We present in this paper a single-step threshold search algorithm and its optical implementation. The proposed algorithm performs magnitude comparison in constant time, independent ...

We report the first observation of a nondipole transition in an ultracold atomic vapor. We excite the 3P-4P electric quadrupole (E2) transition in 23Na confined in a magneto-optical trap, and we demonstrate its application to high-resolution spectroscopy by making the first measurement of the hyperfine structure of the 4P(1/2) level and extracting the magnetic dipole constant A=30.6+/-0.1 MHz. ...

We report the experimental observation of optical data storage by frequency-selective stimulated spin echoes based on electromagnetically induced transparency in an inhomogeneously broadened rare-earth-doped solid. We find that the spin dephasing time T(2) is almost constant in the range 2-6 K, whereas the optical T(2) shortens rapidly above 4 K. This experiment demonstrates the potential of sp...

The temporal behavior of the optical frequency emitted by several DFB lasers under direct square wave modulation was measured using an all-fiber implementation of a Mach–Zender interferometer with an imbalance of 30 ps. The impulse response of the optical frequency to injection current modulation was found to contain a time constant as short as 10–20 ns, together with a few longer ones. The exi...

Coupled nonlinear Schrödinger (CNLS) equations for the fiber couplers with asymmetric selfphase modulation (SPM) and cross-phase modulation (XPM) are studied. With symbolic computation, oneand two-soliton solutions are obtained for the constantand variable-coefficient CNLS equations. Switching dynamics of the solitons is discussed, and effects of the second-order group-velocity dispersion β2, S...