A tunable low-drift laser stabilized to an atomic reference

摘要

We present a laser system with a linewidth and long-term frequency stabilityat the 50 kHz level. It is based on a Ti:Sapphire laser emitting radiation at882 nm which is referenced to an atomic transition. For this, the length of anevacuated transfer cavity is stabilized to a reference laser at 780 nm lockedto the $^{85}$Rb D$_2$-line via modulation transfer spectroscopy. Gaplessfrequency tuning of the spectroscopy laser is realized using the sidebandlocking technique to the transfer cavity. In this configuration, the linewidthof the spectroscopy laser is derived from the transfer cavity, while thelong-term stability is derived from the atomic resonance. Using an opticalfrequency comb, the frequency stability and linewidth of both lasers arecharacterized by comparison against an active hydrogen maser frequency standardand an ultra-narrow linewidth laser, respectively. The laser system presentedhere will be used for spectroscopy of the $1s^{2}2s^{2}2p\ ^{2}P_{1/2} -\^{2}P_{3/2}$ transition in sympathetically cooled Ar$^{13+}$ ions at 441nmafter frequency doubling.