GEOMETRY OF THE FRINGE-FIELD FORMED IN THE INTERSECTION OF 2 GAUSSIANBEAMS

A general expression is obtained for the exact computation of the frin ge field in the intersection volume of two paraxial Gaussian beams for arbitrary beam waist positions and sizes. The expression is then simp lified to allow easy fringe field computation while retaining good acc uracy. By relating the simplified expression to the system parameters relevant to dual-beam laser Doppler velocimeters, simple design equati ons are obtained. These equations permit rapid evaluation of the fring e field variation along the major and minor axes of the intersection v olume and clearly identify the system parameters controlling this vari ation. (C) 1996 Optical Society of America