Abstract

Fluorescence of Li vapor in a heat pipe, excited by the simultaneous action of a laser pulse and Sr collisions, reveals transfer of internal energy from Sr 5¹p₁to Li 4d ²D¹.We detected the excitation vs the wavelength of the transfer light and observed the asymmetric profile predicted from the- ory²⁻⁴ within a spectral range of Δ=20 cm⁻¹ .comparable to the energy mismatch of the intermediate real level （Sr 5p¹ Li 2p²P) and the final level (Sr 5s²¹S₀, Li 4d ²D). The peak cross section, 1.5 X 10⁻¹³ cm² at 1 MW/cm², which appears at an overall energy balance for separate atoms, varies in proportion to and with the square root of the light intensity in the weak and strong signal regimes, respectively, in agreement with theory.

© 1987 Optical Society of America