We report the first observation of a non-dipole transition in an ultra-cold atomic vapor. We excite the 3P-4P electric quadrupole (E2) transition in Na confined in a Magneto-Optical Trap(MOT), and demonstrate its application to high-resolution spectroscopy by making the first measurement of the hyperfine structure of the 4P1/2 level and extracting the magnetic dipole constant A = 30.6 ± 0.1 MHz...

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

We present a new technique for stabilizing and monitoring Bloch oscillations of ultracold atoms in an optical lattice under the action of a constant external force. In the proposed scheme, the atoms also interact with a unidirectionally pumped optical ring cavity whose one arm is collinear with the optical lattice. For weak collective coupling, Bloch oscillations dominate over the collective at...

the purpose of this study was to investigate the effect of heat treatment including solution treatment and aging on the microstructure of cast nickel-based in100 superalloy including size, volume fraction and morphology of primary γ' and different kinds of carbides. for this purpose, different solution heat treatment cycles and a constant aging cycle were implemented on cast ingot samples and t...

designing a power splitter with five ports has been shown in this article. in order to prevent the direct coupling between waveguides, a t-shaped structure with an appropriate distance has been used. the coupling between the parallel photonic crystal waveguides is based on multimode interference, while selecting the output efficiency is performed by setting the refractive coefficients and radiu...

We generalize the optical geometry to include, not only conformally static spacetimes, but any spacetime that admits a hypersurface orthogonal shearless congruence of worldlines. In the generalized optical geometry, which in general is time dependent, photons move with constant speed along spatial geodesics. Gyroscopes moving along spatial geodesics do not precess. We also classify inertial for...

Light field rendering has been proposed to render novel images from a collection of captured images without explicit geometry information. In this report, we present an optical analysis of light field rendering. In particular, a light field rendering system can be considered as a virtual imaging system with a discrete synthetic aperture (e.g., [10]. We define the key elements of the virtual ima...

We present the results of a series of optical, UV, X-ray and γ-ray observations of the BL Lac object S50716+714 carried out by the Swift and AGILE satellites in late 2007 when this blazar was flaring close to its historical maximum at optical frequencies. We have found that the optical through soft X-ray emission, likely due to Synchrotron radiation, was highly variable and displayed a differen...

in this study, friction stir spot welding (fssw) is applied to join the tial6v4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. in this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. microstructural ...

ZnO nanorod was prepared by microwave assisted method. The crystal structure of the nano powders were confirmed by X-Ray diffraction analysis and the mean particle size was estimated by the Scherrer,s formula .The surface morphology of the nano particles were analyzed by   using SEM . The absorption spectrum of the material in the UV-Vis range was recorded .The energy band gap of the...