Gaussian beam divergence using paraxial approximation

Abstract

Gaussian beam intensity follows a normal distribution curve in free space. As it propagates, the divergence and the width increase with distance. Using paraxial approximation, the effect of the distance on the intensity, width, radius of curvature and divergence was investigated. Matlab software was used for characteristics parameters calculation. The divergence angle range (26.67^o≤ θ ≤35.85^o) was obtained at a distance between 3mm and 4mm, and compared with the divergence angle range (43^o≤ θ ≤53^o) obtained experimentally for the distance between 3mm and 4.5mm. The result obtained in this work indicates smaller angles of divergence that can produce a better beam quality and intensity. Finally, this will serve as a great importance for application such as pointing, free space optical communication etc.

Keyword: Gaussian beam, Paraxial approximation, Beam divergence, Normal distribution curve.