Abstract

We analyze the generation of radiation forces in the various internal reflections that occur when a tightly focused, unpolarized Gaussian beam interacts with a dielectric microsphere. The Euler transformation is used to compute the relevant axial-force vectors that are associated with the internal reflections rapidly. The net force is computed as the average of the forces generated by the s- and p-polarization components of the electric-field vector. The force characteristics are strongly dependent on the algebraic value of the index mismatch Δn at the sphere interface. For the two cases of Δn = 0.65, 0.32 with a sphere index n₂ = 1.65, the inclusion of the contributions from the second and third internal reflections after the magnitude of the effective force by at least 10%. For Δn < 0, the individual force contributions from internal reflections beyond the first are at least 4 orders of magnitude less than those of the first interaction. The caustic structures produced by the internal reflections are also profiled for both cases of Δn = ±0.32.

© 1995 Optical Society of America

Single Gaussian beam interaction with a Kerr microsphere: characteristics of the radiation force

Romeric Pobre and Caesar Saloma
Appl. Opt. 36(15) 3515-3520 (1997)

Radiation force on a nonlinear microsphere by a tightly focused Gaussian beam

Romeric Pobre and Caesar Saloma
Appl. Opt. 41(36) 7694-7701 (2002)

Ray optics calculation of the radiation forces exerted on a dielectric sphere in an evanescent field

John Y. Walz
Appl. Opt. 38(25) 5319-5330 (1999)

Optical caustics observed in light scattered by an oblate spheroid

James A. Lock and Feng Xu
Appl. Opt. 49(8) 1288-1304 (2010)

Radiation forces on a microsphere in an arbitrary refractive index profile

Kang Soo Lee, Sang Youl Yoon, Kyung Heon Lee, Sang Bok Kim, Hyung Jin Sung, and Sang Soo Kim
J. Opt. Soc. Am. B 29(3) 407-414 (2012)