Frequency stabilization of multiple violet diode lasers by means of a transfer cavity

A laser stabilization scheme is demonstrated, in which three external-cavity diode lasers (ECDLs) at 397 nm are simultaneously stabilized to a transfer cavity. The cavity is repeatedly scanned and the transmission peaks are compared to those of a 420 nm ECDL locked to a rubidium absorption line. This laser system is designed for laser cooling of a single ⁴³Ca⁺ ion, which is assumed to be a promising candidate for quantum information processing as well as for optical frequency standards. Here the violet diode lasers have to stay within roughly one MHz during the actual experiments.