Statistical properties of modulated dynamic speckles

Statistical properties of the power spectrum of dynamic speckles modulated with the help of a grating are studied. Expressions are obtained for the amplitude, frequency, and width of the information component in the spectrum of scattered radiation modulated by a grating. The experiment carried out with the use of a He-Ne laser demonstrated a good agreement with the conclusions of the theory of the spectral profile of the information component. The possibility for obtaining a narrow (Δf/f-2) component in the spectrum of coherent radiation scattered from a uniformly moving rough surface is shown theoretically and confirmed experimentally.