Abstract

In this work we describe the interaction of relatively high-fluence laser pulses (ϕ≥10 J/cm²) with polished CaF₂ substrates. Both electron impact- and laser ionization-mass spectrometry have been used to probe the material spalled by the fundamental(1.06μ) and harmonic (355 nm and 266 nm) outputs from a Q-switched Nd:YAG laser. Primary ions produced in the source region of a quadrupole mass spectrometer were detected by turning off the eletron impact ionizer, while survey electron impact mass spectra were typically acquired at an energy of 75 eV. A time-of-flight mass spectrometer was modified to permit optical access by both the etching and interrogation laser beams¹. This latter apparatus was used to measure velocity distributions, and to provide optical spectroscopic identification of the ion precursors.

© 1987 Optical Society of America