Abstract

The purpose of the light scattering systems considered here is to obtain information about the macroscopic movements of the scatterer. We shall here be confined to systems based on quasi-elastic scattering - i.e. systems where any change in the frequency of the scattered light is caused only by possible macroscopic motions of the scatterer. A light scattering system can conveniently be divided into three parts (Fig. 1): a transmitter, a receiver, and a signal processor. The transmitter generates a characteristic field (or intensity) distribution in the measuring volume. The receiver collects the scattered light and converts it to an electronic signal (or signals). On the basis of the temporal characteristics of the electronic signal the signal processor will give estimates of the dynamics (e.g. velocity) of the scatterer. The spatial intensity distribution as seen by the receiver when a point scatterer (or set of scatterers) moves through the measuring volume defines the code of the instrument. The code defines how the information about the dynamics of the scatterer is encoded.

© 1989 Optical Society of America