Linewidth and coherence properties of scattered light

The holographic recording of light scattered by brownian particles is discussed. It is shown that, due to the finite time of exposure, the record acts as a temporal filter of non-zero bandwidth. As a consequence the holographic recording can be obtained in spite of the frequency change of the scattered light. The experimental results show that, in fact, such a procedure can constitute an alternative way to measure the linewidth of the scattered light.