Fig. 1: | Nature Communications

Fig. 1

From: Isolated detection of elastic waves driven by the momentum of light

Fig. 1

Experimental setup and geometry. The perspective view on the central part of the experimental setup with the sensor deployed on the HR surface (a) and on the opposite (uncoated) facet (b) for a beam-center to sensor-center separation of x = 12 mm. The x, y, and z axes of the Cartesian coordinate system have the origin at the intersection of the HR surface and the symmetry axis of the beam. For visualization purposes, a part of the sample has been cutout. The laser beam pulse (indigo) impinges on the HR surface (green top layer) of the cylindrical sample (grey) through a tube (black), which prevents scattered light from reaching the sensor head (gold) fixed in the holder arm (dark grey). A minute amount of light (pale blue) is transmitted through the HR layer. The radiation pressure launches elastic waves, which spread away from the source and carry the momentum and energy transferred from the laser pulse. The calculated out-of-plane displacement at time t = 1.96 μs after initial pulse reflection is presented as ripples on the HR surface. The instantaneous z-velocity field of the bulk waves is colour-coded on the cut-out sides of the sample, where the red colour represents positive and blue negative z-velocity. The other experimental positions of the incident beam are depicted with the dashed contours