Compact, Ti:sapphire-based, methane-stabilized optical molecular frequency comb and clock

Abstract

A compact optical clock and frequency comb system is presented, based on a 1 GHz octave-spanning Ti:sapphire laser referenced to the F2(2)(P(7),v3) optical transition in methane at 3.39 microm. The reference methane transition is accessed by a stabilized HeNe laser in a compact transportable format. The output from the octave-spanning Ti:sapphire laser is used to generate a mid-IR comb at the reference wavelength 3.39 microm. Direct comparison of the stabilized optical frequency comb with an ultralow expansion glass cavity-stabilized diode laser at 674 nm shows an Allan deviation of the frequency comb of 3x10(-14) in 20 s.