Measurement of two-photon absorption by gold nanoparticles of different sizes photodeposited onto the core of an optical fibre

Abstract

In this work, the study of two-photon absorption by gold nanoparticles of different diameters photodeposited onto the core of a single-mode optical fibre is presented. The photodeposition of nanoparticles with diameters of 10, 20, 50 and 100 nm was achieved using a continuous wave laser at a wavelength of 1550 nm and a power of 50 mW. Nonlinear optical characterization was carried out by using the P-scan technique of a high gain erbium doped fibre amplifier with pulses of 20 ns at a frequency of 10 kHz, that provides a maximum intensity of approximately 60 MW/cm2. The results show that for gold nanoparticles greater than 20 nm photodeposited onto the fibre, in both cases, the nonlinear coefficient as well as the third-order susceptibility increase as the diameter of the nanoparticles increases, describing a typical behaviour of the two-photon absorption. The obtained results can be used for the design of filters and optical limiters in the communications area.

Short-pulsed Q-switched fiber laser using graphene oxide quantum dots based as saturable absorber

“…Under these conditions, it was possible to determine the values of the non-linear absorption coefficient and non-linear susceptibility , respectively. Recent studies have demonstrated that the modulation depth can be adjusted through the quantity of photodeposited nanostructures on the fiber core, as indicated by the reports presented by Cuvas-Limón et al [ 37 ] and Gómez-Pavón et al [ 38 ]. These studies show that an increase in modulation depth is directly related to an increase in radiation transmission losses during the photodeposition process.…”