Td. Du et Wl. Luo, NONLINEAR-OPTICAL EFFECTS IN FERROFLUIDS INDUCED BY TEMPERATURE AND CONCENTRATION CROSS-COUPLING, Applied physics letters, 72(3), 1998, pp. 272-274
Both experiment and numerical calculation were performed to study the
nonlinear optical (NLO) effects in ferrofluids consisting of magnetic
particles suspended in an organic solvent. We show that, in contrast t
o all the mechanisms responsible for NLO phenomena known so far, the n
ovel NLO effects in ferrofluids in the zero applied field can be expla
ined by the cross coupling between the temperature of the system and t
he concentration of particles through thermophoresis, which in turn le
ads to the spatial distribution of the refractive index. This NLO effe
ct is enhanced by applying a moderate magnetic field whose mechanism i
s unclear so far. (C) 1998 American Institute of Physics.