Re: help needed with a fluorescence microscope

If your sample is transparent (e.g. glass) you can illuminate with blue/UV
light sideways into the edge of your sample. The illuminating light will
spread throughout your sample by total internal reflection.  If you have
etched channels in the device with fluorescently labeled dye in the channels
for visualization, you will probably be able to get illumination into those
channels from the substrate due to good optical index matching between the
fluid and the substrate and also by the high angle of incidence between the
light and the sidewalls of the channels.  You will still want a filter in the
observation optics to reject scattered excitation wavelengths and transmit he
fluorescence (e.g. a Corion long pass interference filter)

Note: Be careful of damaging your eyes with the UV (the effect is delayed but
you will never forget a "sunburn" on your retina).  Also be careful of
electrical noise when a mercury arc lamp is first turned on damaging computers
nearby and also any low light cameras you may be using.

Note #2: You can now get semiconductor lasers with emission wavelengths down
to 400 nm, so you could also use one of these for illumination. e.g. Nokia.

John West
Marketing Director for Microfluidics
Microcosm Technologies  -  CAD software for Microfluidics
www.memcad.com
johnwest@memcad.com