laser, polarized vs. random

Howard Shapiro hms at shapirolab.com
Sat Aug 12 20:06:31 EST 2000


Andrew Beernink writes-

>Can somebody tell me how plarization of lasers impacts flow?  Which is
>recommended?

For a comprehensive discussion of that topic - which should be required
reading for everybody on the Cytometry Mailing List - see Asbury, Uy, and
van den Engh, Cytometry, 2000, 40:88-101.

To quote from that paper, "With anisotropy, two instruments can yield
different results, and both can be right".  However, there is no reason for
widespread panic just yet; the flow cytometer manufacturers usually put the
lasers in the same way in most instruments, i.e., vertically polarized in
the direction of flow, because this orientation is necessary in order to
get detectable orthogonal scatter signals.  Differences in fluorescence
response would be most likely to be seen in instruments with substantially
different geometries in the fluorescence collection optics.  But you should
read the paper.

-Howard




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