Illuminating laser
PIV can be accomplished using continuous wave (CW)
lasers or, more optimally, pulsed lasers. Typical CW lasers
used for PIV are argon-ion lasers producing in the range
of a few watts; for some less demanding applications,
even low-powered helium-neon lasers might suffice.
Typical pulsed lasers are frequency-doubled Nd : YAG
(neodymium : yttrium aluminum garnet) lasers producing
0.1 to 0.3 joules/pulse, at a repetition rate of tens of Hz.
http://www.ias.ac.in/currsci/jul102000/ ... rticle.pdf