  The phenomenon of photonic band gaps in one-dimensional optical lattices is
reviewed using a microscopic approach. Formally equivalent to the transfer
matrix approach in the thermodynamic limit, a microscopic model is required to
study finite-size effects, such as deviations from the Bragg condition.
Microscopic models describing both scalar and vectorial light are proposed, as
well as for two- and three-level atoms. Several analytical results are compared
to experimental data, showing a good agreement.
