Wh. Choi et al., Analysis of optical force and optical potential well for trapping particles near a light-illuminated slit using a finite-difference time-domain method, JPN J A P 1, 39(7A), 2000, pp. 3961-3970
We analyze numerically the optical force and the optical potential well for
trapping a circular-cylinder type object in a near zone of a light-illumin
ated metal slit. Our analysis is based on the finite-difference formulas of
the optical force and the optical potential energy to he developed, a fini
te-difference solution of Maxwell's curl equations, and an absorbing bounda
ry condition to define the problem in a finite region. We show that trappin
g forces induced by the field gradient produced in the vicinity of a slit c
an provide a two-dimensional potential well for trapping nanometric particl
es against a gravitational force. The results may be used to predict the pr
operties of gradient-force traps in a more complicated system.