Elliptic cylindrical pseudo-optical black hole for omnidirectional light absorber

摘要

An elliptic cylindrical omnidirectional light absorber forming a pseudo-optical black hole is studied both analytically and numerically. The conditions for permittivity tensors to trap optical rays are obtained from semiclassical analysis of the ray optic Hamiltonian. The dispersive finite-difference time-domain method is used to study the performance of these light-absorbing structures numerically. It is found that the permittivity of the structure in the form (1∕sinh~u u) ≥ (a∕r)~n traps the light ray efficiently into the elliptic absorber for n ≥ 2, where u is the radial elliptic coordinate and a is the focal distance.