http://confocal-microscopy-list.275.s1.nabble.com/Safe-to-run-multiphoton-laser-at-100-power-for-overnight-continuous-imaging-tp7588726p7588743.html
Your point is taken. This will depend on the type of detector head used. When dealing with ultrafast lasers, I have moved towards using thermal sensors where possible. While they are noisy and slow, they are not prone to non-linearities when using ultrafast pulsed lasers. My understanding of theses thermal sensors is that they are overly not sensitive to angel of incidence, either.
Dr. Christian Wilms / Research & Development Manager
> -----Original Message-----
> From: Steffen Dietzel <
[hidden email]>
> Sent: 26 September 2018 12:17
> Subject: Re: Safe to run multiphoton laser at 100% power for overnight
> continuous imaging?
>
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> Am 26.09.2018 um 11:00 schrieb Christian Wilms:
> > In line with what Craig said, I would suggest you measure the power at the
> sample plane, as well as the power going into the actual microscope
> scanhead (if you can access that point). This will give you an idea of what you
> are actually dealing with.
> But (as far as I know) the usual power meters only give an accurate reading
> with light that falls orthogonally on their surface. So with a high NA objective,
> at the sample plane the measured value would be substantially less than the
> actual power and you only get a 'minimal estimate'. Some people use a 10x
> therefore, which has a low NA. Or you can measure without objective to get
> a maximum estimate, disregarding the less-than-100%-transmission of the
> objective (and the cut-off that does not enter the objective). The true value
> then should be between the two estimates.
>
> Apparently it is virtually impossible to do this measurement at the sample
> plane accurately with the usual tools.
>
> Steffen
>
> --
> ------------------------------------------------------------
> Steffen Dietzel, PD Dr. rer. nat
> Ludwig-Maximilians-Universität München
> Biomedical Center (BMC)
> Head of the Core Facility Bioimaging
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