The Bouguer‐Lambert‐Beer Absorption Law and Non‐Planar Geometries

摘要

The familiar Bouguer‐Lambert‐Beer absorption law, often called Beer's law, is an essential component of many laser ablation propulsion models. However, its treatment in non‐planar conditions requires a consideration of irradiation geometry. Forms of the absorption law are derived for cylindrical and spherical normal incidence geometries, and for conical nozzles with flat and cylindrical targets. The results indicate that use of a concentrating nozzle optic with a transparent target could provide increased impulse generation for laser propulsion. This improvement would be accomplished using a combination of chosen optics and a transparent target material to generate highly confined ablation in‐volume. The surface fluence and ablation depth on a cylindrical target in a parabolic optical nozzle is also derived, and the results are compared to literature raytracing model results and profilometry data, respectively.