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Hello,

Is there anybody out there who has experience with coupling a Mira 900 into
an optical fibre for two photon applications?

We're using a Coherent Mira 900 to do 2P microscopy on our Leica SP2. The
laser beam is coupled in directly to the scan head. But the Setup is a bit
different from the Leica-standard: The laser and the microscope are not
placed on the same optical table. The tables are connected in a quite rigid
way but adjustment of the laser is not very stable and needs fine tuning
before each imaging session (far from beeing comfortable and user friendly).
Also our beam profile is very bad - I think - because of the slightly more
complicated beam path and the increased distance between laser and scanner.
Therefore, I'm thinking about getting the laser fibre-copuled so that I
don't have to worry any more about moving tables. The Leica system for fibre
coupling works only with picosecond-pulse compatible fibres, they say. (Is
there a good single mode fibre for a femtosecond pulsed laser at all?)
Picosecond pulses obviously are a great drawback for 2P microscopy if
penetration depth into the sample is an issue. That's bad for us because we
would like to image quite thick tissue. On the other hand, a better beam
profile and a more homogeneous illumination of the objective back aperture
should result in a better-defined focus and better 2P excitation, hopefully
requiring less laser power. (?) I'm not really sure which way to go...

The guys from Leica are really helpful... But before changing our setup I
would like to make up my mind if it is worth trading pulse width for stable
adjustment and clean focus. (Unfortunately there is no way to mount the
laser on the same table as the microscope.)

Anybody with experience in similar issues who could give some input?
Thanks for any help!

Best Regards,

Olaf


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| Dr. Olaf Selchow                                      |
| SFB 495, Project Z1 - Central Microscopy Facility  |
| Institute of Cell Biology and Immunology           |
| University of Stuttgart                               |
| Allmandring 31, 70569 Stuttgart, Germany              |
| T: +49 711 685 8209, Fax: +49 711 685 7484         |
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