Broadening of the laser radiation spectrum as a result of an increase in the transmission of a nonlinear filter

A theoretical analysis is given of the interaction between laser radiation and a bleachable filter in the presence of mismatch between the working frequency of the filter and the frequency of the laser radiation. It is shown that considerable phase modulation of the radiation may occur as a result of the increase in the transparency of the filter. Estimates are given of the contributions of the amplitude and phase modulation to the width of the spectrum.