title: Tunable cw UV laser with <35 kHz absolute frequency instability for precision spectroscopy of Sr Rydberg states.
abstract: We present a solid-state laser system that generates over 200 mW of continuous-wave, narrowband light, tunable from 316.3 nm - 317.7 nm and 318.0 nm - 319.3 nm. The laser is based on commercially available fiber amplifiers and optical frequency doubling technology, along with sum frequency generation in a periodically poled stoichiometric lithium tantalate crystal. The laser frequency is stabilized to an atomic-referenced high finesse optical transfer cavity. Using a GPS-referenced optical frequency comb we measure a long term frequency instability of < 35 kHz for timescales between 10(-3) s and 10(3) s. As an application we perform spectroscopy of Sr Rydberg states from n = 37 - 81, demonstrating mode-hop-free scans of 24 GHz. In a cold atomic sample we measure Doppler-limited linewidths of 350 kHz.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Bridge
authors.forename: Niamh C
authors.initials: NC
authors.lastname: Keegan
authors.forename: Alistair D
authors.initials: AD
authors.lastname: Bounds
authors.forename: Danielle
authors.initials: D
authors.lastname: Boddy
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Sadler
authors.forename: Matthew P A
authors.initials: MP
authors.lastname: Jones