Stable superconducting magnet

Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training

Pure superposition states of atoms generated by a bichromatic elliptically polarized filed

We find specific polarizations of components of a bichromatic field, which allow one to prepare pure superposition states of atoms, using the coherent population trapping effect. These $m$$-$$m$ states are prepared in the system of Zeeman substates of the ground-state hyperfine levels with arbitrary angular momenta $F_1$ and $F_2$. It is established that, in general case $m\ne 0$, the use of waves with elliptical polarizations ($\epsilon_1$$\perp$$\epsilon_2$ field configuration for alkali metal atoms) is necessary for the pure state preparation. We analytically show an unique advantage of the D1 line of alkali metal atoms, which consists in the possibility to generate pure $m$$-$$m$ states even in the absence of spectral resolution of the excited-state hyperfine levels, contrary to the D2 line.Comment: revtex4, 6 pages including 2 eps figure

What is KASC ?

The organization and functions of the Knowledge Availability System Center are discussed. The KASC is defined as a nonprofit, computerized information center at the University of Pittsburgh. The KASC provides literature searching and referral services designed to identify useful scientific and technical data to its clients. Two types of service are provided: (1) the retrospective search, in which entire reference files are searched, and (2) the current awareness service which provides information on new developments and work being done in related fields. It is stated that the services provided by KASC will reduce duplication of expensive research and aid the movement of new knowledge across industrial, regional, and disciplinary boundaries

History and Developments of Semiconductor Lasers

A brief history of the creation of semiconductor lasers is presented. Basic attention is given to injection lasers including homo- and heterojunction laser diodes, quantum-well heterostructures, quantum cascade systems, etc. General steps in the development of the semiconductor lasers and inventions in the injection lasers are described. Theory modeling the spectral and output characteristics of the laser semiconductor sources is discussed. Set of applied semiconductor materials for laser technology and techniques and number of corresponding lasing wavelengths are listed. In addition, principal fields of application of semiconductor lasers and as well as growing total volume in the laser market are involved. Modern trends in semiconductor quantum electronics are also grounded

Photon Correlation Spectroscopy for Observing Natural Lasers

Natural laser emission may be produced whenever suitable atomic energy levels become overpopulated. Strong evidence for laser emission exists in astronomical sources such as Eta Carinae, and other luminous stars. However, the evidence is indirect in that the laser lines have not yet been spectrally resolved. The lines are theoretically estimated to be extremely narrow, requiring spectral resolutions very much higher (R approx.= 10**8) than possible with ordinary spectroscopy. Such can be attained with photon-correlation spectroscopy on nanosecond timescales, measuring the autocorrelation function of photon arrival times to obtain the coherence time of light, and thus the spectral linewidth. A particular advantage is the insensitivity to spectral, spatial, and temporal shifts of emission-line components due to local velocities and probable variability of 'hot-spots' in the source. A laboratory experiment has been set up, simulating telescopic observations of cosmic laser emission. Numerically simulated observations estimate how laser emission components within realistic spectral and spatial passbands for various candidate sources carry over to observable statistical functions.Comment: Paper presented at the conference 'High Time Resolution Astrophysics', held in Edinburgh, Scotland, September 2007. To appear in D.Phelan, O.Ryan & A.Shearer, eds.,'The Universe at sub-second timescales', AIP Conf.Proc., in press, 2008 (American Institute of Physics, http://www.aip.org/proceedings). 9 pages, 3 figures, 36 reference

Spartan Daily, November 3, 1965

Volume 53, Issue 31https://scholarworks.sjsu.edu/spartandaily/4736/thumbnail.jp