>
> Is a 1mW Green HeNe of any use in "typical" sample scenarios ie; not bright
> actin or tonnes of GFP?  Is the 568 line of an Argon Krypton more useful
> (power vs wavelength)?  What about a diode pumped Nd:YAG 20mW @ 532nm?
>

We have a 1.5mW green NeNe, and it is very useful. To put things in
perspective, on a (different) system where the laser puts out about 14mW
in one line, we usually use 1--3% of that power. Once in a while we need
to go to 10%, or about 1.4mW (at the laser). So a 1mW green HeNe will
do fine assuming that Zeiss does not through away all of that power
with bad coupling.

The Nd:YAG produces 532nm which has a greater chance of picking up the
FITC excitation tail -- you are better off with 543nm.
The 568nm of the Ar/Kr is nice, but these lasers are notorious for having
short lifetimes --the green HeNe will live essentially forever.

There are also yellow HeNe lasers (594nm) which might be great for Texas Red
and many other orange/red emitters. I once posted a question as to why
this laser is not offered as an alternative to the green HeNe. I think
that in a two laser system, the yellow HeNe might be
worthwhile. However, in a three laser system, there is already a red
HeNe (633nm), so it makes more sense to use the Green HeNe, which
gives a more uniformly distributed set of excitation wavelengths, when
used with an argon-ion and red HeNe laser (or diode) laser.

So I vote for the Argon ion/green HeNe/red HeNe configuration.

--aryeh
Aryeh Weiss                          | email: [log in to unmask]
Department of Electronics            | URL:   http://optics.jct.ac.il/~aryeh
Jerusalem College of Technology      | phone: 972-2-6751146
POB 16031                            | FAX:   972-2-6751275
Jerusalem, Israel                    | ham radio: 4X1PB/KA1PB