Anomalous Schottky signals from a laser-cooled ion beam

Low-current, vertical blowup in a stored laser-cooled ion beam

Using a novel technique for real-time transverse beam profile diagnostics of a stored ion beam, we have observed the transverse size of a stored laser-cooled ion beam. Earlier we observed that the density of the beam is independent of the beam current. At very low currents, we observe an abrupt change in this behavior: The vertical beam size increases suddenly by about an order of magnitude. This observation implies a sudden change in the indirect vertical cooling mediated by intrabeam scattering. Our results have serious implications for the ultimate beam quality attainable by laser cooling.

Generation of 90-mW continuous-wave tunable laser light at 280 nm by frequency doubling in a KDP crystal

Laser light at a wavelength of 560 nm from a commercial ring dye laser has been frequency doubled in an external enhancement cavity with a KDP crystal. The cavity employs a new design consisting of only three mirrors, permitting a shorter cavity length as well as compensation for astigmatism and coma. With an input power of ~950 mW of green light, ~90 mW of UV light has been produced. The wavelength of the UV light can be tuned corresponding to +/-3 nm by angle tuning of the crystal, and the optical frequency can be scanned electronically up to +/-10 GHz.