Interaction of Pulses of Different Duration with Chemically Prepared Silver Nanoparticles: Analysis of Optical Nonlinearities

Abstract

The nonlinear optical properties of the aqueous solutions of silver nanoparticles (Ag NPs) prepared by chemical reduction method are analyzed using femtosecond and picosecond pulses at different wavelengths. In the case of 800 and 400 nm, the growths of nonlinear absorption and nonlinear refraction with the increase of Ag NP concentration, as well as a change at the signs of nonlinear optical processes, are determined. The nonlinear absorption coefficient and nonlinear refractive index of Ag NP solutions measured using picosecond pulses were a few orders of magnitude larger than those in the case of femtosecond probe pulses. We also demonstrate the optical limiting properties of Ag NPs using 800 nm, 60 fs pulses.

Effect of Size on the Saturable Absorption and Reverse Saturable Absorption in Silver Nanoparticle and Ultrafast Dynamics at 400 nm

“…Various reports have shown the role of concentration in SA over RSA processes [50]. The result mentioned in this work was compared with the earlier work reported by us [49] where the dependence of the pulse width of the laser pulses on the NLO properties of chemically prepared NPs was investigated. The nonlinear absorption characteristics for Ag NPs at 800 nm in this work were found to be consistent with the We have performed the degenerate pumpprobe measurement of the chemically prepared Ag NPs in deionized water at 400 nm with 35 fs pulses.…”

“…This results in the decrease in the transmittance as the sample further moves toward the focus indicating the combined ramification of SA and TPA processes. Recently, several groups have measured the NLO properties of the Ag NPs with various laser pulse widths [26,48,49]. Particularly, the comparison of the application of 200 ps and 60 fs pulses, which clearly depict the effect of long pulses on the NLO properties of NPs, has been reported in [48].…”

Ag-Nanoparticle-Coupled UV-Responsive Gelatin Nanofiber Photodetectors

“…32,33 The potential schematic by which Ag NPs are incorporated into gelatin nanofibers photodetectors, which results in enhanced device performance, is illustrated in Figure 6 and depicted hereafter. Under UV-light illumination, free electrons in reduced Ag NPs were excited to generate LSPR, 34 where the excited surface plasma induces collective oscillation in its electron density, 35 which has an attractive attribute. A large amount of light was confined inside the gelatin nanofiber device with Ag NPs through oscillation, thereby enhancing the local electromagnetic field.…”

Влияние лазерного разрушения на нелинейно-оптические свойства core/shell наностержней Au/SiO-=SUB=-2-=/SUB=-

“…Наночастицы (НЧ) благородных металлов проявляют уникальные нелинейно-оптические свойства благодаря особому механизму взаимодействия с лазерным излучением, связанному с существованием коллективных электронных возбуждений, называемых в литературе локализованными или поверхностными плазмонами, время жизни которых ограничено и определяется электронэлектронной (∼ 10 2 fs) и электрон-фононной релаксацией (до 10 2 ps) [1][2][3][4][5].…”

“…Для плазмонных НЧ сферической формы [1,2,[6][7][8][9] наблюдают проявления нелинейного поглощения лазерных импульсов. Методом Z-сканирования наблюдают профили нелинейного отклика, характерные для обратного насыщенного поглощения (reverse saturable absorption, RSA) у нанокластеров, и просветления или насыщения поглощения (saturable absorption, SA) у более крупных НЧ.…”