抄録
The hydrodynamic description of the capillary wave at a liquid surface is given, and the method of optical heterodyne detection of the light scattered by the capillary wave is de-scribed. After a short introduction hydrodynamic formulation of capillary wave is given in detail in section 2. In section 3 power spectrum of capillary wave is derived. In section 4 the principle of the heterodyne detection is given, and an example of the detection system is described in section 5.
