Experiments using relatively inexpensive tunable diode lasers are used to study high-resolution absorption spectroscopy in alkali vapors. Direct absorption spectra for cesium and rubidium show adsorption profiles that are Doppler-broadened. A second experiment demonstrates saturated adsorption spectroscopy to remove Doppler broadening in atomic spectroscopy for rubidium atoms in a cell at room temperature. Lamb dips are seen in the Doppler-broadened profiles. Finally a third experiment is described which demonstrate Doppler-free two photon spectroscopy for rubidium vapour. All of these experiments were historical stepping stones toward the creation of a Bose–Einstein condensate.
Abstract Experiments using relatively inexpensive tunable diode lasers are used to study high-resolution absorption spectroscopy in alkali vapor. Direct absorption spectra for cesium and rubidium show adsorption profiles that are Doppler-broadened. A second experiment demonstrates saturated adsorption spectroscopy to remove Doppler broadening in atomic spectroscopy for rubidium atoms in a cell at room temperature. Lamb dips are seen in the Doppler-broadened profiles. Finally, a third experiment is described which demonstrates Doppler-free two-photon spectroscopy for rubidium vapor. All of these experiments were historical stepping stones toward the creation of a Bose–Einstein condensate.
Coherent effects are studied in a dense atomic vapor driven by laser fields. With\noptical properties dramatically modified by these effects, the medium can be used\nto manipulate some of the properties of laser field. Our experiments demonstrate\nthe coherent control over transmission, spatial distribution and noise feature of the\nlaser field interacting with coherent media. The results have potential applications\nin the field such as precision metrology, precision spectroscopy, optical imaging and\nlithography.\nWe develop an experiment to investigate the atomic excitation by few-cycle radio\nfrequency (RF) pulses interacting with Zeeman sublevels. The system provides the\nflexibility to fully control all parameters of RF pulses. Such a flexibility can not be\nachieved in optical domain. Based on this system, experiments can be conducted to\nsimulate processes in ultra-short laser physics. In particular, we study the carrier-envelope\neffect of few-cycle pulses and the strong off-resonant excitation by short\npulses.\nWe also discuss the selective reflection spectrum on a highly dense atomic vapor\nin which the dipole-dipole interaction can not be neglected. The spectrum broadening\ndue to dipole-dipole interaction is much broader than the Doppler broadening. Our\nexperiments show that the excitation by a pump laser can reduce the dipole-dipole\ninteraction, thus reduce the broadening and improve the spectral resolution. The\nexcitation dependence is studied at various atomic densities.