  Spin 1 particle is investigated in 3-dimensional curved space of constant
negative curvature. An extended helicity operator is defined and the variables
are separated in a tetrad-based 10-dimensional Duffin--Kemmer equation in quasi
Cartesian coordinates. The problem is solved exactly in hypergeometric
functions, the quantum states are determined by three quantum numbers. It is
shown that Lobachevsky geometry acts effectively as a medium with simple
reflecting properties. Transition to a massless case of electromagnetic field
is performed.
