Here we report an imprecision below 10-14 with a simple, compact optical frequency standard based upon thermal calcium atoms. Using a Ramsey-Borde spectrometer we excite features with linewidths < 5 kHz for the 1S0-3P1 intercombination line at 657 nm. We have measured a fractional frequency instability below 6 x 10-15 at 1 s, with good prospects for still quieter performance. The key remaining issue is for this standard is how well first- and second-order Doppler drifts can be suppressed. Due to its experimental simplicity such a system could find application as a high stability reference for commercial applications.
Proceedings Title: Proceedings of 2012 IEEE Frequency Control Symposium
Conference Dates: May 21-24, 2012
Conference Location: Baltimore, MD
Conference Title: 2012 IEEE Frequency Control Symposium
Pub Type: Conferences
frequency standards, optical clocks