A potential new frequency/wavelength standard at 778 nm: Doppler free two-photon transitions in rubidium

Abstract

We have stabilized two laser diodes on the hyperfine components of the 5D/sub 3/2/ and 5D/sub 5/2/ two-photon transitions in natural rubidium (v=385 THz). We have carefully investigated the metrological features of these devices. So far we obtain a frequency stability in terms of the Allan variance of 3.10/sup -13/./spl tau//sup - 1/2 / up to 2000 s and a frequency repeatability of the order of 10/sup -12/. The frequency difference between the two devices is 1.7 kHz under identical operating conditions.<>