It is proposed that Bessel light beams be used to pump optical paramet
ric oscillators. The advantages of such pumping are demonstrated by a
comparison with Gaussian light beams. In particular, the maximum mode
coupling coefficient is achieved in a parametric oscillator pumped by
a Bessel beam, which enhances parametric amplification. A nonlinear co
nversion regime that does not destroy the spatial structure of the int
racavity fields is found. This opens up the possibility of increasing
the efficiency of conversion of the energy of an input Bessel beam, co
mpared with a Gaussian beam.