Precursors to the Photo-Ablation of Sodium Trisilicate Glass Due to Uv Excimer Irradiation

ABSTRACTOn polished sodium trisilicate glass surfaces, a fairly distinct threshold in laser fluence is observed to commence ablative etching. An incubation or induction effect is also seen where a series of laser pulses is required to induce etching. In this paper we examine features of the charged particle emission over a broader range of fluences (in particular, at lower fluences) to identify those factors which control the onset of etching. Laser--free electron heating is proposed as a dominant mechanism.