We report on the mechanism of azobenzene polymer surface deformation due to the optical near field around a dielectric sphere that is smaller than the wavelength of the incident light. We compared the deformation pattern on the surface with the calculated intensity distribution of the electric field around the sphere, and analyzed the polymer migration on the polymer surface using tapping-mode atomic force microscopy. This comparison and the polymer migration analysis show that the near-field gradient force induces the surface deformation.

• Received 25 June 2001

DOI:https://doi.org/10.1103/PhysRevB.64.195408