Near-field probing of Bloch surface waves in a dielectric multilayer using photonic force microscopy

Abstract

The potential of photonic force microscopy (PFM) for probing the optical near-field in the vicinity of a dielectric multilayer is demonstrated. An experimental study of Bloch surface waves (BSWs) using PFM is described in detail. The applied technique is based on measuring the BSW-induced gradient force acting on a probe particle combined with precise control of the distance between the particle and the multilayer surface. The BSW-induced potential profile measured using PFM is presented. The force interaction between the probe and the BSW evanescent field is numerically studied. The results indicate that a polystyrene particle with a diameter of 1 μm does not significantly perturb the BSW field and can be used to probe the optical near-field intensity in an elegant, noninvasive manner.