Lasers for cooling and spectroscopy of ⁹Be⁺ and improved UV doubling cavity designs

Laser cooling of Be⁺ ions requires a laser system with a wavelength of 313nm. Several schemes for generating mW levels of 313nm laser light have previously been developed, including second harmonic generation of a dye laser operating at 626nm, sum frequency generation based on a pair of fiber lasers, and frequency tripling of an ECDL. Here, we compare the performance of an ECDL-based laser system to a VECSEL-based laser system for use in a frequency quadrupling approach. In both systems, the initial frequency doubling from 1252nm to 626nm is done using a single pass PPLN waveguide doubler. For the final UV doubling stage from 626 nm to 313nm, we have characterized two resonant UV doubling cavities. One cavity design uses a Brewster cut BBO crystal and another is optimized for an AR-coated, flat facet BBO crystal. We present a comparison of the two 313nm laser systems.