Among the most startling experiences a student encounters is learning that, unlike electrons and other elementary particles, photons have no mass. Under certain circumstances, however, the light quantum behaves as if it did have a finite mass. Starting from Maxwell's equations, we discuss how this arises when light interacts with a charged plasma, or travels along a waveguide. The motion of such photons is analysed using kinematic concepts of special relativity, and we show how a cutoff frequency for effective propagation appears. Seeing how an environment may yield an apparent dynamic mass to the photon paves the way for later understanding: might the Higgs boson field provide other particles, such as the electron, with a mass? This paper is addressed to mid-level physics students, teachers and lecturers, requiring only a knowledge of classical electromagnetic and special relativity theories.

We study the translational motion of two interacting polarizable nanospheres in the presence of a laser field. Dependences of the resulting paths on geometry, viscosity of the medium, polarization, and wavelength of the incident field are discussed. It is found that in general clustering trajectories are more probable thus favoring agglomeration, and that viscosity and circular polarization of the applied field increase further the probability of clustering.

We discuss common features in mechanical, electromagnetic and quantum systems, supporting identical results for the transmission and reflection coefficients of waves arriving perpendicularly at a plane interface. Also, we briefly discuss the origin of special notions such as refractive index in quantum mechanics, massive photons in wave guides and an elementary connection of results for a plane interface to experiments in graphene where the Klein paradox could be tested. The paper is intended for undergraduate level, and a basic knowledge of waves, relativity and quantum physics is required. Its educational purpose is to provide an integrated discussion of waves in order to fit the teaching to the requirement of a shorter sequence of university physics courses.

In this work we present a model for calculating the power radiated by an excited molecule close to metallic objects of spherical or cylindrical shapes. For the case of a molecule near metallic surfaces, we represent it as an oscillating dipole which couples electromagnetically to multipolar moments induced over the corresponding surfaces, and use a formalism similar to that previously developed by the authors for studying SERS. For the interaction of the molecule with a metallic cylinder, the electromagnetic coupling is solved using Green functions. By calculating the local field acting upon the molecule we find signal enhancements of over five orders of magnitude in the radiated power with respect to the radiation of an isolated molecule.

We discuss the transfer of angular momentum from light to classical nanoparticles. An optical torque is induced by a circularly polarized beam, causing the object to rotate. The effect depends on absorption and geometry in such a way that an isotropic dissipationless object is not affected by the external field. Under constant illumination an asymmetric object may rotate uniformly if the light intensity exceeds a minimum value, below which the object executes a rocking motion. These findings are applied to a bioparticle with spheroidal symmetry.