Femtosecond third-order nonlinear spectra of lead-germanium oxide glasses containing silver nanoparticles

Abstract

This work reports on the spectral dependence of both nonlinear refraction and absorption in lead-germanium oxide glasses (PbO-GeO₂) containing silver nanoparticles. We have found that this material is suitable for all-optical switching at telecom wavelengths but at the visible range it behaves either as a saturable absorber or as an optical limiter.

Generation of copper nanoparticles induced by fs-laser irradiation in borosilicate glass

“…The light absorption by nanoparticles produces a coherent and collective oscillation of the electrons, contributing to the enhancement of linear and nonlinear optical properties [1].These properties are influenced not only by the size and the shape of the nanoparticles, but also by the dielectric environment of the host material [3]. Glasses containing metallic nanoparticles are promising materials for photonic applications because they exhibit ultrafast response times and high third order nonlinearities [4].There are several ways to obtain metallic nanoparticles in glass; the most common ones are the melt-quenching, sol-gel, chemical vapor deposition and ion exchange [5]. Although these methods provide a considerable management of the quantities and size of the nanoparticles, none of them allow spatial control of the nanoparticles formation, moreover in the micrometer scale [6,7].…”

Ultrafast third-order optical nonlinearities of heavy metal oxide glasses containing gold nanoparticles

“…Although it has been reported the influence of the metallic nanoparticles in the third-order nonlinear optical susceptibilities for excitation with nano or picosecond laser pulses excitations [6,7,18], the nonlinear refractive index for femtosecond regimes seems to be not sensitive to the presence of nanoparticles for wavelengths within and far from the plasmon band. Such independence was observed for silver nanoparticles in lead-germanium glass [19]. An explanation for this result can be based on the low concentration of the metallic nanoparticles, once the filling factor has been reported to be an important parameter for the enhancement effect of the optical nonlinearities [20].…”

“…3 is directly related to the highly polarizable atoms in the glass matrix, being one order of magnitude larger than the average value of the fused silica for the same wavelength range [2,13]. The results obtained show that for GB glasses n 2 is 1.5 times higher when compared to PGO (PbO-GeO 2 ) glasses containing silver nanoparticles [19], This result is in agreement to the improvement on the v 3 caused by the bismuth oxide in borate glass when compared to lead oxide and it is related to the coordination states around the heavy metal ion [4]. It has been reported that Pb 2+ have fourfold or threefold coordinations in many oxygenated compounds (forming PbO 3 trigonal and/or PbO 4 square pyramids), while Bi 3+ configure polyhedrals with higher coordination numbers (5 -6), being in most cases [BiO 6 ] octrahedral units.…”

Glassy Materials and Light: Part 2

“…Ademais, a introdução de nanopartículas em materiais vítreos pode levar ao engrandecimento de efeitos ópticos não lineares. [32][33][34][35] Em outras palavras, materiais vítreos oferecem grande flexibilidade para modificação da resposta não linear através da manipulação de sua composição.…”