Laser desorption of energetic sodium ions from single-crystal NaNO3 at 1064 nm

We report electron and Na+ ion emission from single-crystal sodium nitrate (similar to 10 eV band gap) upon exposure to IR (1064 nm, 1.16 eV) laser ra diation. The fluence dependence of both the ion and the electron yield is h ighly nonlinear, and the kinetic energies of the emitted ions can reach val ues up to 5 eV. The fluence dependence and the ion energy distributions can be understood by a previously presented model involving multiple photon ch arge transfer plus electrostatic ejection of adions siting atop electron tr aps. Further evidence for the role of defects in the observed ion emission are provided by two-beam experiments; one beam (UV laser) is used to genera te defects and the second beam (IR laser) is used to photodesorb the ions. Such experiments demonstrate that exposure of the sodium nitrate surfaces t o UV laser radiation significantly increases the ion emission due to IR las er radiation.