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Register a new userSpectroscopy of atomic rubidium at 500 bar buffer gas pressure: approaching the thermal equilibrium of dressed atom-light states
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We have recorded fluorescence spectra of the atomic rubidium D-lines in the presence of several hundreds of bars buffer gas pressure. With additional saturation broadening a spectral linewidth comparable to the thermal energy of the atoms in the heated gas cell is achieved. An intensity-dependent blue asymmetry of the spectra is observed, which becomes increasingly pronounced when extrapolating to infinitely high light intensity. We interpret our results as evidence for the dressed (coupled atom-light) states to approach thermal equilibrium.
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We describe measurements demonstrating laser cooling of an atomic gas by means of collisional redistribution of radiation. The experiment uses rubidium atoms in the presence of several hundred bar of argon buffer gas pressure. Frequent collisions in the dense gas transiently shift a far red detuned optical field into resonance, while spontaneous emission occurs close to the unperturbed atomic transition frequency. Evidence for the cooling is obtained both via thermographic imaging and via thermographic deflection spectroscopy. The cooled gas has a density above 10$^{21}$ atoms/cm$^3$, yielding evidence for the laser cooling of a macroscopic ensemble of gas atoms.
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