X.L. Zhu

Observation of metallic indium clusters in thick InGaN layer grown by metal organic chemical vapor deposition

Pure metallic indium clusters of 10–50nm are identified in In0.37Ga0.63N film grown by metal organic chemical vapor deposition based on analysis of x-ray diffraction, transmission electron microscopy, selected area diffraction, and high resolution transmission electron microscopy (HRTEM). The in-plane orientation relationships are InGaN[11−20]‖metallic indium [0−10], InGaN [1−100]‖metallic indium [−101], and InGaN [0001]‖metallic indium [101] along the growth direction. The rocking curve of indium (101) diffraction shows a large full width at half maximum of 3060arcsec, which is consistent with the small size of the indium clusters observed in HRTEM.

Light shift measurements in a diode-laser-pumped /sup 87/Rb maser

Light shifts in a diode-laser-pumped /sup 87/Rb maser under the various conditions of laser intensities and frequency detunings were measured, and a linear dependence of the maser frequency on the laser intensities and frequencies was derived. The pulling coefficient of the maser frequency from the laser was found to be about 2.9/spl times/10/sup -3/, and the light shift could be minimized when the laser frequency was adjusted to near the center frequency of the resonance cell. >

A microwave cavity with low temperature coefficient for passive rubidium frequency standards

Cavity pulling effect has been fully considered in designing of various atomic frequency standards, but quite often it has been neglected for passive rubidium atomic frequency standards (RAFS). This situation may be acceptable for the commonly used RAFS but it is less so for high performance one. A new type of microwave cavity with low temperature coefficient (TC) was designed with coefficient of 28.2 kHz//spl deg/C, which is positive and nearly one order smaller than that of the traditional TE/sub 111/ cavity. Analyses show that the cavity pulling effect of the cavity can be neglected under reasonable temperature stabilization condition. The main cause of the small TC of the cavity was discussed, which is due to the compensation of the positive TC of the dielectric ring in the cavity to the negative TC of the metal part of the cavity.

Diode‐laser isotope enrichment of rubidium with a polarized atomic beam

Diode‐laser isotope enrichment of rubidium by magnetic deflection of a polarized atomic beam has been experimentally studied with laser‐induced fluorescence detection. The abundance of 85Rb was enhanced from the natural value of 72.8% to 97% and that of 87Rb, from 27.2% to 83%. The results were compared with those with hot‐wire detection.