Large spectral tunability of narrow geometric resonances of periodic arrays of metallic nanoparticles in a nematic liquid crystal

摘要

We investigated the geometric resonances of periodic arrays of gold nanoparticles embedded in a nematic liquid crystal using a semi-analytical method. By changing the liquid crystal's refractive index seen by the scattered light propagating along the array axis, the geometric resonance can be modulated according to an analytical law. The spectral tunability is proportional to the index difference (n_e-n_0) of the liquid crystal and the interparticle distance i.e., Ak = (n_e-n_0)d, which is as large as 100 nm. The large and easily controlled tunability of this compound structure makes it desirable for design of plasmon-based sensors and switches.