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

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.

Temperature dependence of electric field noise above gold surfaces.

Electric field noise from fluctuating patch potentials is a significant problem for a broad range of precision experiments, including trapped ion quantum computation and single spin detection. Recent results demonstrated strong suppression of this noise by cryogenic cooling, suggesting an underlying thermal process. We present measurements characterizing the temperature and frequency dependence of the noise from 7 to 100 K, using a single Sr+ ion trapped 75 mum above the surface of a gold plated surface electrode ion trap. The noise amplitude is observed to have an approximate 1/f spectrum around 1 MHz, and grows rapidly with temperature as T;{beta} for beta from 2 to 4. The data are consistent with microfabricated cantilever measurements of noncontact friction but do not extrapolate to the dc measurements with neutral atoms or contact potential probes.