Origin of optical nonlinearity for PbO, TiO2, K2O, and SiO2 optical glasses

Abstract

The nonlinear optical properties for the PbO, TiO2, K2O, and SiO2 system have been measured by the Z-scan method. The magnitude and sign of the nonlinear refractive index n2 were determined, as was the negative sign, which indicated a self-defocusing optical nonlinearity. Two optical absorption bands at 540 and 660 nm, respectively, are observed in the optical absorption spectra. The sources of the absorption bands are attributed to the 3d-shell electronic transitions of Ti3+ ions from the ground state to the excited states. The origin of the negative nonlinear refractive index was the contribution of resonant electronic transition processes, which can cancel the positive nonresonant refractive index that mainly resulted from the hyperpolarizabilities of the Pb–O and Ti–O pairs.

Induced crystallization and physical properties of Li2O–CaF2–P2O5:TiO2 glass system

“…Additionally, the spectrum of each glass-ceramic sample exhibited two clearly resolved absorption bands at about 510 and 680 nm. These bands are assigned to 2 B 2g → 2 B 1g and 2 B 2g → 2 A 1g transitions of Ti 3+ ions, respectively [6][7][8]; with a gradual increase in the concentration of TiO 2 in the range 0-0.6 mol%, the half width and intensity of these two bands are observed to decrease. The summary of the data on the positions of various bands in the optical absorption spectra of Li 2 O-CaF 2 -P 2 O 5 :TiO 2 glass-ceramics are presented in Table 1 From the observed absorption edges, we have estimated the optical band gaps (E 0 ) of these samples by drawing Urbach plots ( Fig.…”

Two-photon optical absorption in PbO-SiO2 glasses

“…In addition, optical properties are relatively simple, in which the optical absorption edge is governed by electronic transitions in Pb atoms. 14,15 In addition, the glass exhibits interesting optical properties, such as marked photochromic effects, 16 -18 large photosensitivity, 19 and high nonlinear refractivity [20][21][22][23] including second-order nonlinearity. 24,25 However, the origins of these phenomena have not yet been understood satisfactorily, and some fundamental insights will be valuable.…”

Preparation and the optical nonlinearity of surface chemistry improved titania nanoparticles in poly(methyl methacrylate)–titania hybrid thin films

“…In terms of the atomic bonding, the positive nonresonant refractive index possibly results from the hyperpolarizabilities of the Ti-O pairs, as reported by Zhu et al for TiO 2 -containing glass [31]. Up to now, the degree of nanoparticle's interface passivation is not perfect.…”