Wavelength-Dependent Nonlinear Optical Properties of Ag Nanoparticles Dispersed in a Glass Host

Abstract

The linear and nonlinear optical properties of metal nanoparticles are highly tunable by variation of parameters such as particle size, shape, composition, and environment. To fully exploit this tunability, however, quantitative information on nonlinear absorption cross sections is required, as well as a sufficient understanding of the physical mechanism underlying these nonlinearities. In this work, we present a detailed and systematic investigation of the wavelength-dependent nonlinear optical properties of Ag nanoparticles embedded in a glass host, in which the most important parameters determining the nonlinear behavior of the system are characterized. This allows a proper quantification of absorption cross sections and elucidation of the excitation mechanism. Based on small-angle X-ray scattering measurements average particle diameters of 3 and 17 nm are estimated for the studied samples. The nonlinear optical properties of the nanoparticle−glass composite are studied in an extended wavelength range with the open aperture z-scan technique. The experiments reveal a strong dependence of the nonlinear optical response on the excitation wavelength. Based on the wavelengthdependent response, excited-state absorption is determined as the excitation mechanism of the nanoparticles. Electromagnetic simulations demonstrate that the contributions from electric field enhancement and plasmonic coupling between the particles in the diluted glasses are limited, which implies that the very high two-photon absorption cross section at 460 nm ((6.9 ± 1.6) × 10 6 GM for the 3 nm particles and (19.5 ± 2.2) × 10 9 GM for the 17 nm particles) is an intrinsic property. In addition, irradiance-dependent measurements elucidate the role of saturation of the excited-state absorption process on the observed nonlinearities.

Effects of External Field Wavelength and Solvation on the Photophysical Property and Optical Nonlinearity of 1,3-Thiazolium-5-Thiolates Mesoionic Compound

“…Therefore, the field of optical materials has been exploring how to develop new compounds with tunable photophysical properties or enhanced (hyper)polarizabilities for a long time. [4][5][6] So far, researchers have successfully recognized a variety of molecules with exciting optical properties, including inorganic complexes, [7][8][9] organic molecules, [10][11][12][13] metal clusters, 14,15 doped polarizable electrides, 16,17 and even macrocyclic compounds with special topology, 6,18,19 and applied some of them into practice. Among them, the conjugated organic chromophores with electron donating and electron accepting groups at both ends were one of the most popular optical units, partially due to their convenient structural tailoring.…”

The nonlinear optical properties of silver nanoparticles decorated glass obtained from sintering mesoporous powders

“…Particularly, the intrinsic loss of plasmatic energy of Ag NPs at visible frequencies is lower than other noble metallic NPs, which can give rise to SPR 39 and the larger s−d energy separation of Ag NPs could made contribution to the valences electrons’ free transportation and improve the oscillator strengths in Ag NPs 23 . According to the former research the NLO properties of the embedded Ag NPs reveal a close correlation of the excitation wavelength 40 . At moderate irradiances, the electrons of Ag NPs are pumped from the ground‐state to the excited state along with the bleaching of the ground‐state Plasmon absorption band, which generally manifests saturated absorption (SA).…”

“…23 According to the former research the NLO properties of the embedded Ag NPs reveal a close correlation of the excitation wavelength. 40 At moderate irradiances, the electrons of Ag NPs are pumped from the ground-state to the excited state along with the bleaching of the ground-state Plasmon absorption band, which generally manifests saturated absorption (SA). When the excitation wavelength is close to the SPR wavelength, the ground-state plasma will bleach and free carrier absorption occur, which lead to the transformation from the SA to the RSA 38 when the irradiances is intensity.…”

Study of Tunable Plasmonic, Photoluminscence, and Nonlinear Optical Behavior of Ag Nanoclusters Embedded in a Glass Matrix for Multifunctional Applications

“…The two photon absorption coefficient (β) of the Ag nanoclusters incorporated into the glass matrix annealed at 600 °C shows the highest absorption coefficient while the sample annealed at 650 °C shows a decrease value of the two photon absorption coefficient (β). This is due to the optical limiting threshold conditions that got reduced after thermal treatment at the high temperature as the Ag nanoclusters became larger . The reason behind the presence of two photon absorption in these samples with the excitation at 800 nm could be based on the intra band (s‐p) transitions (or) free carrier absorption since the absorption band (≈420 nm) of the samples is nearer to the SPR band of Ag nanoparticles.…”