High-Resolution Saturation Spectroscopy of the SodiumDLines with a Pulsed Tunable Dye Laser

Abstract

The sodium D resonance lines have been studied in saturated absorption with a repetitively pulsed tunable dye laser. The hyperfine splitting of the 3 S&g2 and 3 P&y2 states of Na~is resolved. Measurements with a delayed probe reveal a remanent hole burning in the velocity distributions of the two ground-state levels, caused by a velocity-selective optical pumping cycle. A time-resolved observation of the collisional-velocity thermalization in the presence of Ar buffer gas is reported.In the past the techniques of laser saturation spectroscopy' ' that eliminate Doppler broadening by spectral hole burning have essentially been restricted to either gas-laser transitions or molecular transitions in accidental coincidence.Although organic-dye lasers have been tuned to atomic resonance lines, " they generally did not provide the required spectral resolution and stability. The present paper reports on a study of the sodium resonance lines D, at 5896 A and D, 0 at 5890 A in saturated absorption using a repetitively pulsed tunable dye laser with an instrumental bandwidth of 7 MHz and a pulse length of 30 nsec. The use of a pulsed laser source is made possible by a recently introduced sensitive technique of saturation spectroscopy. " Two light beams of equal frequency are sent in opposite directions through the resonant atomic vapor, and the change in absorption for one of the beams, the probe, caused by the other, the bleaching or saturating beam, is recorded. A Nl TROGE N TUNABLE

Holographie spectro-temporelle

“…La technique à'absorption saturée consiste à analyser, par transmission d'un faisceau monochromatique accordable, ce « trou » de largeur 2xr no m creusé dans le profil de la bande d'absorption. D'abord appliquées aux vapeurs atomiques, où l'élargissement inhomogène est produit par l'effet Doppler [4], ces méthodes spectroscopiques se sont ensuite étendues aux solides [5][6][7].…”

Optics in Nanotechnology

“…Pulses or flashes of red light of 8 ns durations with a record color definition (bandwidth) of 0.0004 Å (or 0.001 cm À1 or 30 MHz) and energy of~1 nJ per pulse were achieved (Hansch laser). In addition to being narrow band, the laser allows for change (tuning) of wavelength with good control and precision, a pivotal property for matching (resonating with) and studying electronic structure of atoms and molecules [96]. John Hall, on the other hand, used a different approach by starting out with the red light of a helium-neon gas laser [97,98].…”

“…Figure 10.32 (left top) is a photo from a celebration at Stanford recognizing Schawlow and Hansch as California Scientist of the year for these developments and the use of the narrowband tunable laser in precise spectroscopic measurements. Issa Shahin, a doctoral student in the Stanford group, was involved in using the narrow bandband dye laser to study the structure of sodium and hydrogen [96]. Munir Nayfeh, a doctoral student under the superposition of Hansch and Schawlow reproduced a variation to the Jan Hall's stable He-Ne light source (.…”

Saturation spectroscopy for optically thick atomic samples

“…The saturation spectroscopy technique employing dye lasers was introduced by Hdnsch et al 2 In order to avoid power broadening of the Doppler-free signals, normally modest pump-beam intensities are used. At the line center only a small fractional change in the transmitted probebeam intensity is then obtained for samples typically absorbing half the probe-beam light.…”