Enhanced optoelastic interaction range in liquid crystals with negative dielectric anisotropy

International audienceWe demonstrate that the long-range interaction between surface-functionalized microparticles immersed a nematic liquid crystal--a "nematic colloid"--and a laser-induced "ghost colloid" can be enhanced by a low-voltage quasistatic electric field when the nematic mesophase has a negative dielectric anisotropy. The optoelastic trapping distance is shown to be enhanced by a factor up to 2.5 in presence of an electric field. Experimental data are quantitatively described with a theoretical model accounting for the spatial overlap between the orientational distortions around the microparticle and those induced by the trapping light beam itself