Enhanced Thermal Lens Effect in Gold Nanoparticle-Doped Lyotropic Liquid Crystal by Nanoparticle Clustering Probed by Z-Scan Technique

This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich's method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n (2) increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering.