Electrodynamic features of the optimal near-field above the rough quartz surface in the photochemical polishing methods

Abstract

Two photochemical nano-polishing techniques for rough quartz surfaces are compared in terms of electrodynamics. The numerical modelling of the evanescent field configuration near the quartz surface is considered. The finite-element approach is used to solve the Helmholtz two-dimensional vector equation. The quartz surface coated with a liquid containing chlorine molecules is illuminated both from the quartz side and the liquid side. The efficiency is quantitatively estimated in both cases (an approximate nine-time difference in the irradiation source power is needed to obtain identical results). The results show that the features of the field formed by spatial spectrum components of the surface in both techniques are similar. But the interference between the incident wave and wave reflected from some interface spatial spectrum harmonics can affect the contrast of the evanescent field when the total internal reflection occurs. This should be taken into account when polishing a surface with a periodic profile.