Comment on “Nonlinear optical properties in SrTiO3 thin films by pulsed laser deposition” Solid State Communications 135 (2005) 221–225

Effect of lanthanum doping on linear and nonlinear-optical properties of Bi3TiNbO9 thin films

“…The magnitudes ofǐ ncrease with La 3+ content of LBTN-x thin films except L4 sample. The magnitude ofˇdepends on impurity band [19]. The total effective intermediate-level density increases with the La 3+ content of LBTN-x.…”

“…Since the bandgap in LBTN-x (3.269-3.525 eV) is larger than the excitation energy of the laser (2hv = 3.1 eV), 2PA can not be attributed to a direct transition process. However, 2PA can occur at 800 nm in LBTN-x thin films from strong laser pulse with intermediate levels in the forbidden gap induced by impurities [19].…”