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Q: Fachverband Quantenoptik und Photonik
Q 64: Precision measurements and metrology VI
Q 64.1: Vortrag
Freitag, 22. März 2013, 14:00–14:15, E 001
A long reference cavity with contribution from thermal noise to frequency instability of below 10−16 — •Sebastian Häfner, Stefan Vogt, Stephan Falke, Christian Lisdat, and Uwe Sterr — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig
The stability of current optical clocks is limited through the short-term stability of the interrogation laser.
Here, we will focus on the reference cavity of the clock laser system, whose mechanical length stability provides the frequency stability of the clock laser.
The length stability of well designed and operated cavities is limited by the Brownian motion of the materials, especially of the mirrors.
This influence can be reduced by using longer cavities at the cost of a higher sensitivity to vibrations and more difficult thermal control.
Our laser system uses a 47.7 cm long ULE high finesse cavity which is to our knowledge the longest cavity ever used for frequency stabilization of a laser, with expected frequency instability from thermal noise of Δν / ν = 8· 10−17.
We have designed a new cavity mounting which shows a measured acceleration sensitivity of Δ l/l=4·10−11/g and a precision temperature control system with expected temperature instability of below 10 µK.
To fully benefit from the cavities stability, we are planing to control all fluctuations of the optical path length from the end mirror of the cavity to the experiment.
This work is supported by the Centre for Quantum Engineering and Space-Time Research (QUEST)
and EU through the Space Optical Clocks (SOC2) project.