Direct Creation of Excitonic Molecules in CuCl by Giant Two-Photon Absorption

Abstract

The two-photon absorption spectrum due to excitonic molecules is measured in CuCl at 77 and 4.2\ifmmode^\circ\else\textdegree\fi{}K. We measured values of the two-photon transition cross section of the order of ${10}^{\ensuremath{-}44}$ ${\mathrm{cm}}^{4}$ sec and estimated a peak value of ${10}^{\ensuremath{-}42}$. The binding energy of the molecule is found to be 255 ${\mathrm{cm}}^{\ensuremath{-}1}$.