C. Saloma et Mo. Cambaliza, SINGLE-GAUSSIAN-BEAM INTERACTION WITH A DIELECTRIC MICROSPHERE - RADIATION FORCES, MULTIPLE INTERNAL REFLECTIONS, AND CAUSTIC STRUCTURES, Applied optics, 34(18), 1995, pp. 3522-3528
We analyze the generation of radiation forces in the various internal
reflections that occur when a tightly focused, unpolarized Gaussian be
am interacts with a dielectric microsphere. The Euler transformation i
s used to compute the relevant axial-force vectors that are associated
with the internal reflections rapidly. The net force is computed as t
he average of the forces generated by the s- and p-polarization compon
ents of the electric-field vector. The force characteristics are stron
gly dependent on the algebraic value of the index mismatch Delta n at
the sphere interface. For the two cases of Delta n = 0.65, 0.32 with a
sphere index n(2) = 1.65, the inclusion of the contributions from the
second and third internal reflections after the magnitude of the effe
ctive force by at least 10%. For Delta n < 0, the individual force con
tributions from internal reflections beyond the first are at least 4 o
rders of magnitude less than those of the first interaction. The caust
ic structures produced by the internal reflections are also profiled f
or both cases of Delta n = +/-0.32.