http://confocal-microscopy-list.275.s1.nabble.com/405-laser-intensity-at-the-objective-is-0-15-of-actually-intensity-is-this-normal-tp7587264p7587276.html
disc. If I recall, it was "increased" to something like 14% with the X1,
not sure where it is with the W1. Maybe a bad dichroic in the disc? And,
really easy. I used to work for Andor and with a single-mode I remember
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>
> I took a closer look at your reported power levels along the optical
> train. First, recognize that most silicon-based power meters are not
> accurate at 405nm. There could be an error there as high as 20%. Also, as
> previously mentioned, these sensors are angle dependent and you might not
> be capturing all the light because of beam size (at the back of the
> objective perhaps, but probably fine at laser and fiber tip). But assuming
> you've taken those points into consideration and you're confident in the
> powers you've indicated, there's something a bit more troubling here.
>
> You mentioned this system uses a multi-mode fiber delivery method, but the
> incurred losses are much higher from laser to fiber tip than I would
> expect, and from fiber to objective, even more so. This is a very
> inefficient illumination setup - at all wavelengths.
>
> Disclaimer - I work for Andor. Andor (Spectral Applied Research) in the
> past manufactured the Borealis multi-mode fibre illumination upgrade for
> Yokogawa CSUs, and so I have some familiarity with what efficiency levels
> should be achievable with a multi-mode fiber delivery scheme. Here, it
> seems it's not much better than a single-mode fiber approach, so if I were
> you, I'd get this checked out with the manufacturer.
>
> John Oreopoulos
>
> > On Sep 6, 2017, at 3:54 PM, John Oreopoulos <
[hidden email]>
> wrote:
> >
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> posting.
> > *****
> >
> > Emmanuel,
> >
> > Check and make sure you don't have a filter inserted into the optical
> pathway that blocks the 405nm wavelength, and then check that all the other
> filters (dichroic and emission) actually are what you think they are. Make
> sure the filter wheels and linear motor positions are indexed and homing
> properly. Check your microscope filter turret as well.
> >
> > John Oreopoulos
> >
> >> On Sep 6, 2017, at 3:28 PM, Emmanuel Levy <
[hidden email]>
> wrote:
> >>
> >> *****
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> posting.
> >> *****
> >>
> >> Dear Peter,
> >>
> >> Thank you for this information.
> >>
> >> Are you running your lasers at full power?
> >>
> >>
> >> Yes we are.
> >>
> >>
> >>> What combiner are you using?
> >>
> >>
> >> It is a custom made combiner, from the company that assembled the
> >> microscope.
> >>
> >>
> >>> I can't comment so much on the power you have at your objective but on
> >>> your combiner side the values look low. Going into a multi-mode fibre
> >>> should be like a barn door for your lasers so if we imagine a ~5% (x2)
> loss
> >>> due to combining optics and an ~80% coupling efficiency, you should
> still
> >>> be getting a ~72% average coupling efficiency into the fibre. It
> sounds to
> >>> me like the setup may need to be realigned. If you still don't see an
> >>> improvement then one other possibility is that the 405nm laser has
> degraded
> >>> your fibre due to solarisation and the fibre needs replacing.
> >>
> >> Thanks a lot for this info, I'll discuss it with the company.
> >>
> >> If there are other opinions, in particular regarding the loss between te
> >> fiber-output and the objective, I'd be glad to hear them.
> >>
> >> Best wishes,
> >>
> >> Emmanuel
> >>
> >>
> >>
> >>
> >>
> >>>
> >>> I hope this helps.
> >>>
> >>>
> >>> Kind Regards
> >>>
> >>> Pete Brunt
> >>>
>
Dept. of Molecular Biology