title: Giant nonlinear optical properties of bismuth thin films grown by pulsed laser deposition.
abstract: Thin films of Bi were grown by pulsed laser deposition on glass substrates at room temperature. The thickness and roughness of the films were characterized by grazing-incidence x-ray reflectivity, and the complex refractive indices were measured in the range from 1.5 to 4 eV by spectroscopic ellipsometry. We performed Z-scan measurements to study the third-order optical nonlinearity of the films. It was found that the Bi films exhibited an unusually large nonlinear refractive coefficient, n(I)~1.24x10(-1) cm(2)/kW and nonlinear absorption coefficient, alpha(I)~-3.97 cm/W , at low laser intensity, ~60 kW/cm(2) . This anomaly is believed to have an origin related to melting of the Bi films at the focus spot by the laser beam.
authors.forename: D R
authors.initials: DR
authors.lastname: Liu
authors.forename: K S
authors.initials: KS
authors.lastname: Wu
authors.forename: M F
authors.initials: MF
authors.lastname: Shih
authors.forename: M Y
authors.initials: MY
authors.lastname: Chern