Broadband Superfluorescent Source Based on Bismuth-Doped GeO2-SiO2 Fiber

The first bismuth-doped superfluorescent fibersource operating at 1.44-μm was developed. Atpump power of 200 mW and pump wavelength of1310 nm, its output signal reaches 57 mW withspectrum width of 25 nm

Logarithmically Slow Expansion of Hot Bubbles in Gases

We report logarithmically slow expansion of hot bubbles in gases in the process of cooling. A model problem first solved, when the temperature has compact support. Then temperature profile decaying exponentially at large distances is considered. The periphery of the bubble is shown to remain essentially static ("glassy") in the process of cooling until it is taken over by a logarithmically slowly expanding "core". An analytical solution to the problem is obtained by matched asymptotic expansion. This problem gives an example of how logarithmic corrections enter dynamic scaling.Comment: 4 pages, 1 figur