  A simple and convenient procedure for single-shot, single-spot ablation
threshold measurement has been developed. It is based on the employment of
cylindrical lens to obtain elliptical Gaussian laser spot. The ablated spot
chords which are parallel to the minor axis were measured across the spot major
axis which is proportional to the fluence cross-section thus providing wide
range dependence of damaged spot size versus fluence in one spot measurement.
For both conventional and new-developed procedures the ablation threshold for
typical Nd:YAG laser parameters (1064 nm, 10 ns) has been measured as 50 mJ/cm2
which is one order of magnitude lower than that for a bulk graphite.
