12 research outputs found
Consequences of the background in piezoresponse force microscopy on the imaging of ferroelectric domain structures
Transformation of singular light beams at nondegenerated four-wave mixing in dye solutions
Local electromechanical response at a single ferroelectric domain wall in lithium niobate
Optically driven oscillations of ellipsoidal particles. Part I: Experimental observations
We report experimental observations of the mechanical effects of light on ellipsoidal micrometresized dielectric particles, in water as the continuous medium. The particles, made of polystyrene, have shapes varying between near disk-like (aspect ratio k = 0.2) to very elongated needle-like (k = 8). Rather than the very tightly focused beam geometry of optical tweezers, we use a moderately focused laser beam to manipulate particles individually by optical levitation. The geometry allows us varying the longitudinal position of the particle, and to capture images perpendicular to the beam axis. Experiments show that moderate-k particles are radially trapped with their long axis lying parallel to the beam. Conversely, elongated (k > 3) or flattened (k < 0.3) ellipsoids never come to rest, and permanently “dance” around the beam, through coupled translation-rotation motions....Méthodes avancées pour la caractérisation optique de systèmes particulaires complexesEuropean ITN COMPLOID