Ultrahigh long-term dimensional stability of a sapphire cryogenic optical resonator.
We report on the ultrahigh long-term dimensional stability of a crystalline cryogenic optical resonator (CORE) cooled to liquid-helium temperature. The frequency of a Nd:YAG laser stabilized to a CORE was compared over long times with an independent laser system, a frequency-doubled Nd:YAG laser stabilized to a hyperfine line of molecular iodine at 532 nm. Over a 6-month period the drift was less than 3 kHz. The dimensional stability of the CORE is thus more than 2 orders of magnitude higher than that of the best ultralow-expansion glass ceramic cavities at room temperature.
Storz
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R
Fakultät für Physik, Universität Konstanz, D-78457 Konstanz, Germany.
Braxmaier
C
C
Jäck
K
K
Pradl
O
O
Schiller
S
S