Posted by
Michael Giacomelli on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Shearing-Interferometer-with-Ti-Sapph-tp7585684p7585690.html
*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopyPost images on
http://www.imgur.com and include the link in your posting.
*****
Hi Tim,
A shearing interferometer is not going to work with an ultrafast
laser. There is a note in the thorlabs catalog that can help you
figure out what it will work with:
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=2970The model you have has a 21.16 mm difference in optical pathlength, so
you will need a coherence length at least that long. Try your laser
in CW mode, although even that may not be quite 2 cm depending on how
stable it is without a mode lock. Usually though testing for
collimation after a beam expander doesn't require an interferometer
since the beam is large the divergence is low. Have you tried just
bouncing it across the room and back with a mirror?
Mike
On Wed, Sep 21, 2016 at 12:07 AM, Tim <
[hidden email]> 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.
> *****
>
> Hello, we recently purchased a shearing interferometer from Thorlabs (Part # SI254) to test collimation after beam expansion in our two-photon microscope setup. The strange thing is we cannot seem to get an interference pattern either before or after beam expansion (varying the distance between the lenses in the beam expander). We do see the pattern clearly if we try on a simple laser diode. Does anyone have experience looking at the shearing interferometer pattern with a Ti-Sapphire laser or have any ideas what may be causing our problem?
>
> Thanks for any help,
> Tim