Tuning hyper-Rayleigh scattering amplitude on magnetic colloids by means of an external magnetic field

Influence of Magnetic Field on the Two-Photon Absorption and Hyper-Rayleigh Scattering of Manganese–Zinc Ferrite Nanoparticles

“…The incidence of light in a dielectric medium results in the polarization of electrons that are subjected to a specific potential depending on the material constituents. 51,52 As discussed in detail in previous work, 33 in the present case electrons are subjected to the resultant potential of the manganese−zinc ferrite, that is, Mn 0.5 Zn 0.5 Fe 2 O 4 . Therefore, this group of atoms corresponds to the basic unity of light and matter interaction.…”

“…This can be seen as the signal intensity is modified when the shape and size of the nanoparticle is changed, as well as the material, when comparing the obtained results with previous ones from magnetite (Fe 3 O 4 ) nanoparticles also coated with oleic acid molecules. 33 To calculate the hyperpolarizability for both samples, the external reference method was used, with magnetite nanoparticles synthesized by Chemicell, Fluid-MAG-OS, as reference, since their hyperpolarizability was already determined. 33 Therefore, for the sample containing spherical nanoparticles β ○ = (9.5 ± 0.2) × 10 −28 cm 5 /esu, while for cubic ones, β □ = (7.8 ± 0.1) × 10 −28 cm 5 /esu.…”

“…33 To calculate the hyperpolarizability for both samples, the external reference method was used, with magnetite nanoparticles synthesized by Chemicell, Fluid-MAG-OS, as reference, since their hyperpolarizability was already determined. 33 Therefore, for the sample containing spherical nanoparticles β ○ = (9.5 ± 0.2) × 10 −28 cm 5 /esu, while for cubic ones, β □ = (7.8 ± 0.1) × 10 −28 cm 5 /esu.…”

“…Nonlinear optical (NLO) properties of ferrofluids were studied for optical limiting applications, 20 on colloidal solutions and thin-films, 29,30 in the presence of external magnetic field, 31 as well as the nonlinear scattering of maghemite 32 and of magnetite NPs in the presence of external magnetic fields. 33 Despite some attention being directed to NLO phenomena in magnetic colloids, exhaustive characterization of nonlinear properties of other ferrites has not been performed, and information about the origin of the nonlinearities is lacking in the literature, as well as the ultrafast dynamics of the charge carriers. A comprehensive understanding of the optical properties of magnetic nanoparticles, in particular, under the influence of external magnetic fields, contributes to the development of new photonic, optofluidic, and magneto-optical devices.…”

Propriedades ópticas não lineares de segunda e terceira ordem de coloides magnéticos

“…No entanto, a diferençaé desprezável quando comparada com os erros experimentais (±0,001). Como observado anteriormente [101,112], campos magnéticos com magnitudes menores que 1600 Oe não são suficientes para influenciar o espectro de atenuação de nanopartículas de magnetita. Portanto, a pequena mudança observada aqui, mesmo para um campo externo de maior magnitude,é um indicativo de um menor momento magnético das nanopartículas de ferrite estudadas quando comparadas com nanopartículas de magnetita de diâmetros semelhantes.…”