http://confocal-microscopy-list.275.s1.nabble.com/Objective-phosphorescence-tp7587588p7587606.html
no glue) showed the brightest luminescence. Also, the glass in optical
as clear as an optical fiber, you could clearly see the bottom. As was
they should show a similar low level of luminescence to optical fibers. If
> *****
> To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> Post images on
http://www.imgur.com and include the link in your posting.
> *****
>
> Dear all,
>
> from my experiences with fiber optics and microscopes, I would expect that
> the additional luminescence might come more from the used glue to fix the
> lenses within the objectives. I guess for manufacturing reasons, to reduce
> the times for polymerization often UV hardening might be used. As long as a
> light beam just passes the lenses, there is only little issue (we are using
> laser light for widefield illumination of the microscope stage, but we
> don't have issues with such a background), in case the LED light is able to
> be spread within the objective casing, some luminescence might excited
> within the glue and part of it will be guided through the optical system as
> well.
>
> Could the LED light be better shaped, such that I travels mainly through
> the lenses?
>
> with best regards,
>
> Gerhard
>
>
> Dr. Gerhard Holst
> Head of Science & Research
> +49 (0) 9441 2005 0
> +49 (0) 172 711 6049
>
> PCO AG, Donaupark 11, 93309 Kelheim, Germany, www.pco.de
> USt. ID-Nr. / VAT: DE128590843, Registergericht / Register court:
> Regensburg HRB 9157
> Sitz der Gesellschaft / Registered office: Kelheim, Vorstand / Chairman:
> Dr. Emil Ott
> Vorsitzender des Aufsichtsrats / Chairman of the supervisory board: Johann
> Plöb
>
>
> -----Ursprüngliche Nachricht-----
> Von: Confocal Microscopy List [mailto:
[hidden email]]
> Im Auftrag von Martin Wessendorf
> Gesendet: Mittwoch, 22. November 2017 00:16
> An:
[hidden email]
> Betreff: Re: Objective phosphorescence
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> Post images on
http://www.imgur.com and include the link in your posting.
> *****
>
> Interesting. I was using the widefield 'scope in my lab today and saw
> something that I've seen a thousand times before, but never thought
> about: Near-UV excitation causes the optics in my sub-stage condenser to
> fluoresce yellow. However, as others have said, I don't know whether the
> source is the glue, the glass, or the housing.
>
> Martin Wessendorf
>
>
>
>
> On 11/20/2017 9:33 PM, Benjamin E Smith wrote:
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> >
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> > Post images on
http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> > Hey microscopists,
> > We observed an odd phenomenon today on a microscope and was
> > wondering if anyone else has ever seen it. We were using a DMD do a
> > full field flash with 420nm light during the flyback of the scanning
> > mirror on a 2P imaging rig. We noticed that after the light was
> > turned off, there was a millisecond long slewing of the signal that
> > looked a lot like phosphorescence. In the following image, you can
> > see that the LED is on for the first portion of the scan, then turns
> > off and the apparent
> > afterglow:
https://goo.gl/2ENHwL> >
> > This afterglow was also apparent with an oscilloscope looking at the
> > PMT and fast mirror signals:
https://goo.gl/2AMsvB> >
> > We then systematically removed components from the optical path,
> > and cleaned everything, and we were eventually able to determine that
> > the glass in the objective itself was glowing, where if the objective
> > was removed and the DMD image was shined onto a piece of lens paper or
> > metal, the afterglow went away:
> >
https://goo.gl/arXYF5> >
https://goo.gl/cVo2Ev> >
> > The final nail in the coffin to our suspicions was when we then
> > mounted a plano-convex N-BK7 lens onto the microscope and the effect
> > came back, and the thicker the lens, the stronger the effect. Also,
> > the effect went away when we used 540nm light.
> >
> > With a bit of internet searching I also came across this paper that
> > confirms there is some visible fluorescence in glass due to trace
> elements:
> >
http://www.schott.com/d/advanced_optics/87330898-4e56-4d70-965a-3f03c7> > bc0c80/1.1/schott_tie-36_fluorescence_of_optical_glass_us.pdf
> >
> > Even when I saw the slew, and the first thing that came to mind was
> > phosphorescence, the last thing that came to mind was that the glass
> > in the objective itself was the offender, so I wanted to post this to
> > both give other people a heads-up, and also to see if anyone else has
> > run into this phenomenon.
> >
> > Cheers,
> > Ben Smith
> >
>
> --
> Martin Wessendorf, Ph.D. office: (612) 626-0145
> Assoc Prof, Dept Neuroscience lab: (612) 624-2991
> University of Minnesota Preferred FAX: (612) 624-8118
> 6-145 Jackson Hall, 321 Church St. SE Dept Fax: (612) 626-5009
> Minneapolis, MN 55455 e-mail:
[hidden email]
>
Benjamin E. Smith, Ph. D.