Atomic physics

  • Rydberg measurement: work on experimental uncertainties: we measure hydrogen emission lines in the visible range, using a CCD spectrometer. Estimation of measurement uncertainties (systematic error: check spectrometer calibration using a laser or spectral lamp, correct if necessary; random error: instrument resolution). Data processing (measurements and uncertainties) using Kaleidagraph-type software enables the model to be validated(chi2 calculation) and a Rydberg measurement and its accuracy to be deduced.
  • Fluorescence of ruby excited by a dye laser : fluorescence of a ruby crystal excited by a pulsed dye laser, pumped by a nitrogen laser. The radiative lifetime of an excited state of the ruby crystal is measured with a photomultiplier (computer recording and use of data analysis software) and it is shown that the fluorescence wavelength is independent of the laser excitation wavelength, which varies from 560 to 610 nm, but depends on temperature and the direction of excitation polarization relative to the crystal axes. Application to the realization of a fiber-optic thermometer probe using a modulated LED.
  • Fluorescence and absorption of a dye, rhodamine, and ruby: We measure the spectrum of a dye (rhodamine) and then of a ruby crystal in the entire visible range using a fiber-optic spectrometer interfaced to a PC. We then observe the spectrum of excitation-induced fluorescence using a nitrogen laser, as well as that of a dye laser (again rhodamine). We then measure lifetime as a function of temperature: pulse excitation and direct observation of decay time (PC-based data acquisition and analysis system).
  • Hanle effect or Larmor precession (in progress): this effect corresponds to the action of a magnetic field on an atomic magnetic moment. We observe the evolution, as a function of the field, of the polarization state of light re-emitted by a mercury atom previously optically excited. This effect indirectly enables us to observe energy shifts (Zeeman shifts) that are much smaller than the Doppler width.
  • Vibrational energy of the nitrogen molecule : Le spectre d’émission de la molécule d’azote est obtenu par une décharge électrique radiofréquence dans de l’azote gazeux. Les nombreuses transitions vibroniques observées permettent de déterminer les niveaux d’énergie de vibration de deux états électroniques excités. Ces niveaux sont ensuite analysés avec le modèle de l’oscillateur de Morse.
  • Infrared absorption spectrum of the HCl molecule
  • Iodine molecule: laser excitation-induced fluorescence spectroscopy experiment using a green He-Ne laser at 543nm. Recording of the spectrum using a high-resolution grating spectrometer (1cm-1, i.e. approx. 20,000). Analysis of vibration and rotation levels and determination of interatomic interaction potential.
Published on 13 March 2017
Updated on 13 March 2017