Re: Dichroic mirror double reflections issue

Posted by Sripad Ram-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Dichroic-mirror-double-reflections-issue-tp7584577p7584580.html

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Hi Yan,
The issue sounds like the dichroic does not have an anti-reflection coating
on the non-reflective side. From the URL it was not clear if the optic has
the AR coating. Also are you using the dichroic at 45 degree incidence.

HTH

Sripad

On Wed, Dec 30, 2015 at 10:05 AM, Yan, Lu <[hidden email]> wrote:

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>
> Hi there,
>
> I recently bought a dichroic mirror from Chroma (2mm thick reflecting
> fluorescence,
> https://www.chroma.com/products/custom-inventory/nc302987-zt670dcrb) for
> our confocal fluorescence microscopy setup. But I found that with the
> reflective side oriented correctly, at the reflection band, the reflected
> beams seemed splitting into two and partially overlapping with each other
> (ghost image?). This happens at a wide range of incident angles, and as I
> rotated the dichroic (changing the angle), the "overlapped" reflection
> alternated between partially overlapping and two distinct separated (by a
> dark line in the middle) half circular beams.
>
> Images of single fluorescence bead also showed 'side lobes'. So I was
> wondering if anyone has experience on how to eliminate such effect? Is this
> common for dichroics? Or it is specific for the one I have and I should get
> another one?
>
> Thank you very much in advance, and I wish you all Happy New Year!
>
> Lu
> -----------------------------------------------------
> Lu Yan
> Nanostructured Fibers and Nonlinear Optics Laboratory
> Electrical and Computer Engineering
> Boston University
> 8 St. Mary St., Boston, MA, 02215
> 617.353.0286 (office) | 617.358.5917 (lab)
> [hidden email]
> -----------------------------------------------------
>