Posted by
Craig Brideau on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Beam-quality-of-SHG-generated-laser-source-for-FLIM-tp7586574p7586575.html
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If your crystal really is 10mm thick, you are using way too thick a
crystal. You are probably getting a great deal of 'walk off' as the phase
matching will be all over the place. Typically for this you want to use 10
to 100 um (micro!) thick crystal and a bit of focusing. You can still get
some spatial chirp and walkoff even with a thin crystal, but I successfully
coupled a doubled Ti:Saph into single mode fiber (without destroying the
fiber) using a setup I detail in my paper:
http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2195758You need a freespace solution as fiber coupling can introduce phase noise
into the system, but a simple high energy pinhole should suffice.
Feel free to contact me if you have any questions.
Craig
On Mon, Mar 6, 2017 at 2:33 PM, Tim <
[hidden email]> wrote:
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>
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>
> Hi everyone, our application is FLIM microscopy with a pulsed visible
> source. Since we have a 100 fs Ti-Sapphire laser, we thought we could
> generate our pulsed source using a BIBO crystal (10 mm thickness). We end
> up getting very high SHG conversion for 960 nm -> 480 nm (300 mW average
> power at 480 nm) but when we try to focus this beam down we cannot get
> anywhere close to a diffraction limited performance. Does anyone have
> experience using frequency doubled laser source for imaging? What can we do
> to 'clean up' this frequency doubled beam and how much power can we expect
> to lose?
>
> Thanks for any help,
> Tim
>