Re: Trying to image Cy7.5 -- AxioObserver.Z1 blocking IR?

Posted by Craig Brideau on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Trying-to-image-Cy7-5-AxioObserver-Z1-blocking-IR-tp7586976p7586977.html

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Are you very sure your dichroics and excitation filters are appropriate for
the long wavelengths you are using? Some visible coating filters have
unusual spikes in the NIR because they were never intended to work in that
range. This is not uncommon among longpass filters, which can act more like
unpredictable bandpass filters if you are using them outside their stated
wavelength ranges.

Craig


On Tue, Jul 11, 2017 at 1:47 PM, Cammer, Michael <[hidden email]
> wrote:

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>
> A few weeks ago we asked about finding a light source at 780ish nm for
> exciting Cy7.5.  As always, people on this listserv provided very helpful
> suggestions.  We were able to get a pE-4000 system with multiple LEDs but
> are finding that the Zeiss AxioObserver.Z1 fluorescence illumination optics
> appear to be cutting wavelengths above 700 nm.
>
> We adjusted the LED powers such that 635, 660, 740, and 770 nm all have 52
> mW at the end of the liquid light guide.  We removed the IR filter for the
> autofocus system that is in the objectives nosepiece.  However, the light
> at 740 and 770 nm is blocked from arriving at the objective lenses.
>
> Does anyone know whether there is a filter somewhere else in the light
> path we could easily remove to pass these wavelengths or is this a
> limitation of the light train?
>
> (graphs of the power loss posted at http://microscopynotes.com/
> axioobserver/IR/ )
> Thank you!!
>
> =*===========================================================*=
> Michael Cammer, DART Microscopy Laboratory, NYU Langone Medical Center
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