Espectroscopia não-linear de alta resolução em I2, Ti e Ar+
AUTOR(ES)
Flavio Caldas da Cruz
DATA DE PUBLICAÇÃO
1994
RESUMO
In this work we performed nonlinear high-resolution spectroscopy in I2, Ti and Ar+. Iodine was used as a wavelength reference in the visible. Doppler limited spectra of this molecule were obtained, in particular by using photoacoustic detection. This one proved to be comparable to detection with photodetectors in terms of sensibility and signal-to-noise ratio. Saturation spectroscopy was used to resolve the hyperfine structure of several rotovibrational lines. Among these we resolve the hyperfine structure of the R(115) 20-1line, at 570 nm, which is an interesting frequency reference for the resonant transition of magnesium, at 285 nm, when frequency doubled lasers are used to investigate this one. The R(115) 20-1 hyperfine spectrum was reproduced by considering the electric quadrupole and spin-rotation terms. By performing a least-square fit we determined the coupling constants D eQq e D C for this transition at first order. The resonant transition of magnesium is used for laser cooling of this element which is of interest for applications in new time and frequency standards. Titanium was studied in hollow-cathode lamps by intermodulated optogalvanic spectroscopy (IMOGS) and nonlinear Hanle effect (NLHE). For the 3P0®3D10 transition of this element, at 592 nm, we determined by IMOGS: its wavenumber relative to the iodine Doppler limited spectrum with an accuracy of 3.10-7; the isotopic shifts of the even isotopes of this element; the upper level Landé factor and the homogeneous transition linewidth. Other configurations of saturation spectroscopy were used as well. By NLHE we determined the upper state homogeneous width of that transition. A theoretical analysis of the NLHE for a J"=0® J =1 transition in the presence of colisional excitation is also presented. The nonlinear Hanle effect in Ar+ laser transitions was studied by optogalvanic detection. We detected the optogalvanic signal as a function of a longitudinal magnetic field for the 514,496,488 and 476 nm lines. The NLHE in the upper level of the 496 and 476 nm lines were also observed by detecting the fluorescence of the 454.5 and 472.7 nm lines, which share the upper level with the 496 and 476 lines. A discussion of the curve shapes obtained by optogalvanic and fluorescence detection is presented. Using these curves we were able to determine the homogeneous width of the metaestable upper level of lines 496,488 and 476 nm
