Soliton-mediated orientational ordering of gold nanorods and birefringence in plasmonic suspensions.

We report on the soliton-mediated orientational ordering of gold nanorods in a colloidal plasmonic suspension. Due to the nonlinear optical response of the suspension, a light beam forms an optical spatial soliton which creates an effective optical waveguide. The orientation of the nanorods along the waveguide is regulated by the optical torque exerted by the linearly polarized soliton beam.

Guiding and nonlinear coupling of light in plasmonic nanosuspensions.

We demonstrate two different types of coupled beam propagation dynamics in colloidal gold nanosuspensions. In the first case, an infrared (IR) probe beam (1064 nm) is guided by a low-power visible beam (532 nm) in a gold nanosphere or in nanorod suspensions due to the formation of a plasmonic resonant soliton. Although the IR beam does not experience nonlinear self-action effects, even at high power levels, needle-like deep penetration of both beams through otherwise highly dissipative suspensions is realized.