A simple digital system for tuning and long-term frequency stabilisation   of a CW Ti:Sapphire laser
  We have implemented a simple and cost-effective digital system for long-term frequency stabilisation and locking to an arbitrary wavelength of the single-frequency ring CW Ti:Sapphire laser. This system is built around two confocal Fabry-Perot cavities, one of which is used to narrow short-term line width of the laser and the other to improve long-term stability of the laser frequency. The second interferometer is also in the path of the radiation from an external-cavity diode laser stabilized to an atomic transition. Our system is an extension of a commercial Tekhnoscan laser lock. This system has been successfully used in experiments on high-resolution laser spectroscopy of ultracold Rydberg atoms. 
I.I. Beterov, A. Markovski, S.M. Kobtsev, E.A. Yakshina, V.M. Entin,   D.B. Tretyakov, V.I. Baraulya, and I.I. Ryabtsev
physics.optics