Journal of the Optical Society of America B
Comparative photon statistics of several ultraviolet laser systems determined by transient two-photon absorption
Douglas J. Bamford, A. P. Hickman, Mark J. Dyer, William K. Bischel
Abstract
The photon statistics of several different laser systems operating at 226 nm are probed by measuring absolutely the fluorescence following two-photon absorption in atomic oxygen. The integrated fluorescence, obtained by scanning the laser frequency through the two-photon resonance, is theoretically shown to be proportional to G(2) (0) σ0(2). The second-order intensity-correlation function at time zero, G(2)(0), characterizes the laser, and σ0(2) is a fundamental atomic property. Measurement of the integrated fluorescence permits determination of the relative value of G(2) (0) for each laser. The assumption that G(2)(0) = 1 for one of the lasers, a single-frequency source, allows G(2)(0) for the other lasers to be placed on an absolute scale. The values thereby obtained range from 0.8 ± 0.2 to 3.2 ± 0.4. Different values are obtained when the radiation is generated by frequency mixing or Raman shifting of the same frequency-doubled visible dye laser, suggesting that frequency-conversion processes have a significant effect on G(2)(0).