An optical pumping experiment is described where the pumped rubidium atoms were submitted to an acoustic vibration. A modulation in the transmitted light was observed when the acoustic frequency matched the Larmor precession frequency. An interpretation of the experimental observations could not be found.
Recently a distributed Bragg reflection (DBR) laser diode was commercialised by SDL (USA) for helium optical pumping experiments. An interesting feature of the new device is the possibility of frequency modulation of the diode output by modulating the current intensity, leading to a new pumping scheme called optical pumping with frequency modulated light. We develop this method to induce spin precession and obtain new resonances in 4He atomic gas, simply by modulating the frequency of the pumping light at the Larmor frequency of atomic states in a static magnetic field. These resonances are analysed with a simple model taking into account velocity changing collisions.
This thesis presents a study on the realisation of a usable rubidium atomic beam inside a sealed vapour cell. A velocity selective optical pumping scheme was implemented to enable the detection of atoms of a particular velocity class travelling between two separated laser beams. This represents a new spectroscopic technique, the usefulness of which has been demonstrated through its applications. In the present work, the vapour cell atomic beam has been used to measure Larmor precession of polarised atoms in a magnetic field and one-dimensional laser cooling.
Abstract : A method for the optical observation of nutational resonance in optically pumped rubidium vapor has been studied both experimentally and theoretically. The method consists of pulsemodulating an rf magnetic field a one of the Zeeman resonance frequencies of the vapor and observing the resulting damped transient modulation in the transmitted light intensity. Of particular interest is the application of this method to a study of the spin relaxation of vapor atoms as influenced by the physical parameters of the system, in the case where the applied steady magnetic field is intense enough to cause individual Zeeman intervals to become noticeably unequal. Both single and double quantum resonances at a wide spectrum of Zeeman transitions of Rb-85 vapor diffusing through neon and helium buffer gases have been observed and identified, and the damping of the transient nutations in light intensity has been recorded under a variety of conditions. (Author)
We have experimentally demonstrated a new type of noise spectroscopy, which requires neither amplitude nor frequency noise of the light source. A highly stabilized diode laser provides low-noise light for the optical magnetic resonance of Rb atoms. The laser light transmitted through the Rb vapor contains significant intensity fluctuations whose power spectrum has a distinct peak at the Larmor frequency. The fluctuations are spontaneously generated by the atoms and are attributed to the stochastic properties of the photon scattering which randomly interrupts the Larmor precession of the atomic magnetic moment.
A type of double resonance experiment is reported in which resonance fluorescence from an atomic vapour is excited by modulated light. The amplitude of modulation of the fluorescent light undergoes changes which indicate an atomic resonance when the frequency of modulation is equal to the Larmor frequency of the atoms in an applied magnetic field, or equal to twice that frequency. The effects have been studied in the intercombination line, λ 3261 A, of cadmium. They are in good agreement with theoretical predictions. The method could be applied to the spectroscopy of excited atoms.