  In this work we show that single horizon black hole behaves as a "laser". It
is in many aspects conceptually analogous to Corley and Jacobson work on the
two horizon black hole "laser". We started by proposition that circumference of
the black hole horizon holds the natural (integer) quantum number of
corresponding reduced Compton's wave length of some boson systems in great
canonical ensemble. For macroscopic black hole ground state is practically
totally occupied while other states are practically totally unoccupied which is
a typical Bose condensation. Number of the systems in this condensate
represents black hole entropy. For microscopic black hole few lowest energy
levels are occupied with almost equivalent population (with negative chemical
potential) while all other energy states (with positive chemical potential) are
practically unoccupied. It implies that here not only spontaneous but also
stimulated emission of radiation comparable with spontaneous emission occurs.
By Hawking evaporation any macroscopic black hole turns out in a microscopic
black hole that yields, in a significant degree, coherent stimulated emission
of the radiation. It implies that by total black hole evaporation there is no
decoherence, i.e. information loss. Finally, a mass duality characteristic for
suggested black hole model corresponding to string T-duality is discussed.
