Tunable 397 nm Light Source for Laser Cooling of Ca Ions Based on Frequency Doubling of Diode Laser

Abstract
We have fabricated an rf ion trap and laser-cooling light sources to observe shelving transition in a single calcium ion. All the radiation required for laser cooling and observation of the transition can be prepared with diode lasers in this system. Continuous-wave radiation at 397 nm for laser cooling was generated by frequency doubling of a GaAlAs laser in an external enhancement cavity. As a preliminary experiment for observing the shelving transition, laser cooling of one hundred calcium ions was demonstrated using this radiation and another diode laser.