Posted by
Craig Brideau on
Mar 31, 2021; 7:47pm
URL: http://confocal-microscopy-list.275.s1.nabble.com/polarization-and-dichroics-tp7592058p7592061.html
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Polarization is actually one of my research focuses. The primary dichroic
in particular can alter your polarization fairly strongly. This is mainly
an issue if you don't have pure S or P states (+) relative to the dichroic
surface. Any 45 or -45 content (x) will be likely ellipticized by the
coating layers, and if you already have elliptical light then it starts
becoming very complicated. This is problematic as we discovered that under
certain conditions fluorophores exhibit "interesting" responses to
polarized light. We actually observed different fluorescence rises with
calcium concentration using XRhod using different polarization states for
excitation. This implies that if you use certain polarization states you
will get significantly different results with your experiment! Here's a
couple of our papers on the subject, and a couple additional papers on my
similar work with polarized CARS microscopy.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5459219/https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8207/82076C/Polarization-dependent-responses-of-fluorescent-indicators-partitioned-into-myelinated-axons/10.1117/12.908976.shorthttps://www.researchgate.net/publication/258711286_Automated_Control_of_Optical_Polarization_for_Nonlinear_Microscopyhttps://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-24/issue-4/046502/Excitation-parameters-optimized-for-coherent-anti-Stokes-Raman-scattering-imaging/10.1117/1.JBO.24.4.046502.fullEnjoy!
Craig
On Wed, Mar 31, 2021 at 11:37 AM Antonio Jose Pereira <
[hidden email]> wrote:
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>
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>
> Hi all,
>
> I'm resorting to those of you who are experienced with anisotropy
> measurements or polarization optics in general. I might need a long-pass
> dichroic beamsplitter at 45ยบ, but where the longer wavelengths
> (fluorescence) will pass through the dichroic backwards. I mean that light
> from the source is to be reflected, whereas the fluorescent light is to be
> transmitted back to the source. Polarization preservation upon reflection
> is not important for me, but preservation upon (backwards) transmission is.
>
> I reckon that taming polarization states with dichroics (and virtually all
> optical elements) is already an issue. I wonder how much more it will be by
> using the dichroic in such geometry.
> Or maybe there other optical elements better suited for this purpose?
>
> Thanks in advance for any comment or suggestion,
> Antonio
>