Quantitative analysis of resonant third-harmonic generation in strontium

Absolute intensity measurements of resonant third-harmonic generation in a Sr-Xe mixture have been performed using a flash-lamp-pumped dye laser. The third-harmonic power increased by about 3 orders of magnitude with respect to the pure Sr system by adjusting a pressure ratio of $\frac{p_{\mathrm{Xe}}}{p_{\mathrm{Sr}}}=53\mathrm{}$. Excellent agreement with theory is obtained provided the absorption cross section ${\sigma }_3=3.5\mathrm{}\times {10}^{-18\mathrm{}}$ ${\mathrm{cm}}^2$ of Sr at the third-harmonic wavelength of 191.97 nm has been taken into account. The absorption cross section limits the conversion efficiency to 2 × ${10}^{-5\mathrm{}}$ for an input intensity of 5 × ${10}^6$ W/${\mathrm{cm}}^2$. Up to these intensities no saturation effects were observed.