Lasers produce a lime green which has frequency of 532nm,
which is very close to the peak of the eye's sensitivity.
The greens and blues produced by a typical argon are further
away from the peak response of the eye, so they appear to
be dimmer in comparison.
is why DPSS laser are said to be 3 to 4 times brighter than
a typical argon laser. So a 100mW DPSS laser will look the
equivalent to a 300mw argon laser in terms of apparent brightness.
this to an extreme, if you were to compare a 100mw 532nm Diode
laser with a 2W Infrared Laser e.g. emitting 1064nm, the 100mW
laser will look much brighter because the human eye can't
see infrared wavelengths!