  We develop an analytical formalism for studying optical analogues of
spherically symmetric black-hole spacetimes. We demonstrate the exact
similarity between the electromagnetic wave equations in an inhomogeneous
medium in flat spacetime and those in a general-relativistic curved spacetime
respectively. The permittivity and the permeability of an inhomogeneous optical
medium act as metric components of the analogue spacetime. Manifest properties
of black holes like curved light trajectories follow directly from our
formalism. Other black-hole phenomena like quasinormal modes can also be
studied within this framework. We extend the above formalism and obtain an
approximate analogue for the case of purely dielectric media. These optical
black holes can be employed to investigate black-hole phenomena with table-top
experiments.
