H. Cousin et al., AN AUTOFOCUS SYSTEM FOR REPRODUCIBLE FOCUSING IN LASER-ABLATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY, Spectrochimica acta, Part B: Atomic spectroscopy, 50(1), 1995, pp. 63-66
A method of controlling the focus position of the ablating laser was e
valuated. This system consists of a displacement measuring unit based
on the triangulation displacement measurement principle. A simple prel
iminary experimental setup with a light source (LED, light emitting di
ode) and a displacement sensor (PSD, position sensing detector) with o
ptics and a electronic circuit, resulted in a reproducibility of a giv
en lateral position of +/-5 mu m. A fine-tuning of the components, as
well as the use of a laser diode as a light source wilt certainty impr
ove this value.