Injection locking of a low cost high power laser diode at 461 nm

Stable laser sources at 461 nm are important for optical cooling of strontium atoms. In most existing experiments this wavelength is obtained by frequency doubling infrared lasers, since blue laser diodes either have low power or large emission bandwidths. Here, we show that injecting less than 10 mW of monomode laser radiation into a blue multimode 500 mW high power laser diode is capable of slaving at least 50% of the power to the desired frequency. We verify the emission bandwidth reduction by saturation spectroscopy on a strontium gas cell and by direct beating of the slave with the master laser. We also demonstrate that the laser can efficiently be used within the Zeeman slower for optical cooling of a strontium atomic beam.Comment: 2nd corrected version (minor revisions); Manuscript accepted for publication in Review of Scientific Instruments; 5 pages, 6 figure

Three-vortex configurations in trapped Bose-Einstein condensates

We report on the creation of three-vortex clusters in a $^{87}Rb$ Bose-Einstein condensate by oscillatory excitation of the condensate. This procedure can create vortices of both circulation, so that we are able to create several types of vortex clusters using the same mechanism. The three-vortex configurations are dominated by two types, namely, an equilateral-triangle arrangement and a linear arrangement. We interpret these most stable configurations respectively as three vortices with the same circulation, and as a vortex-antivortex-vortex cluster. The linear configurations are very likely the first experimental signatures of predicted stationary vortex clusters.Comment: 4 pages, 4 figure

UPGRADED M501G OPERATING EXPERIENCE

ABSTRACT In 2003 the M501G at Mitsubishi's in-house combined cycle power plant facility located at Takasago (T-Point) was upgraded. The upgrade was accomplished by replacing some of the existing hardware in the M501G gas turbine, for further improvements in output and heat rate. The verification testing at this power plant has been continuing with MHI's latest upgraded combustor technology, that has successfully demonstrated NOx levels at 15ppm and 9ppm or lower emission levels in Mitsubishi's G and F gas turbines, respectively. The upgraded M501G has been officially designated as the M501G1 gas turbine. This paper describes the upgraded hardware and the operating experience at the T-Point power plant