Re: LEDs

Posted by Ippei Kotera on
URL: http://confocal-microscopy-list.275.s1.nabble.com/LEDs-tp4283200p7322927.html

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Hi Julio,

You need to use surface power density (W/m^2) if you want to know which
illumination system bleaches chromophores faster. Total power at the
focal plane cannot be used for photobleaching comparison unless the
illumination area is held constant.

> Incidentally, I originally performed the comparison between microscopes because some of our users think lasers are used on microscopes because they have more power than mercury lamp (or similar) illumination, and also that a laser based microscope will bleach the sample more than one with a lamp. I was trying to show that this is not true. In fact, we could easily get 10-20 mW at the focal plane with lamps and filters for most excitation bands on most of our microscopes, which is more than the nominal power of any laser line on our confocal (some of which are no stronger than a laser pointer), and definitely much more than the actual power we would use for imaging.

Ippei

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Ippei Kotera, PhD

Centre for Research in Neurodegenerative Diseases
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