The best but most expensive solution is holographic notch filters. They have
very strong, up to 6 orders of magnitude attenuation of the laser line, with
75-85% transmission of all other wavelentghs. They are really nice and pass all
the emitted signal as they don't even attenuate the tails of the specta. The
cost about $1500 each. However when you improve the front end signal being
measured by a $100,000+ instrument you have to ask yourself if it is worth it.
Obviously we do.

Jim Turner

Milton Charlton wrote:

> Is there any consensus on which manufacturer's emission filters have the
> highest transmittance?  I want to replace emission filters on our Biorad
> 600.  Has anyone noticed any improvement when emission filters were replaced?
>  I have also noticed that the 488nm excitation filter looks burnt at
> a particular viewing angle.  Replacing this gave a little more light but
> we always use the densest ND filter for excitation anyway so this did not
> help much.
> Thanks
> Milton Charlton
>
> Milton P. Charlton
> Professor
> Physiology Department, Med.Sci. Bldg. 3232
> MRC Group
> University of Toronto
> 1 King's College Circle
> Toronto, ON, M5S1A8
> Canada
> tel:416-978-6355
> fax:416-978-4940
> email: [log in to unmask]