A SIMPLIFIED CAVITY ANALYSIS FOR ESTIMATING ENERGY COUPLING DURING LASER-ABLATION AND DRILLING OF SOLIDS - THEORY

A radiative cavity analysis is developed to estimate the change in las er energy coupling with a solid opaque target as a function of the cav ity shape and size, and the heat transfer in a target. The approach of the analysis is to examine the departure in the net energy absorbed b y a target due to the formation of a cavity, from that absorbed by a f lat surface. The development of a general departure function, f, is pr esented, complete with the assumptions made and their implications on the resulting analysis. A specific f for a typical laser ablation proc ess and common cavity geometry is also given in algebraic form. The me aning of the terms contained within f are discussed with respect to la ser energy coupling in solids, and the range of validity of the theory is examined. (C) 1998 Elsevier Science B.V.