Re: Laser beam sharing via multi-mode fibers

Posted by Sudipta Maiti on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Laser-beam-sharing-via-multi-mode-fibers-tp7584037p7584043.html

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A mirror on a good quality translation stage may be more stable. Of
course, a large core (50 microns or bigger) multimode fiber is rather
forgiving and a flip mount may do just fine.
Sudipta
On Thu, 30 Jul 2015 01:12:34 -0700, Joshua Vaughan wrote
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> *****
>
> Dear Kyle,
>
> I believe a good flipper mount would have sufficient return accuracy
> when aligned carefully to flip in the plane of the mirror (e.g.,
> 'sideways') but it is a little bit of a hassle and someone will
> eventually bump the mirror.
>
> How about using a polarizer to split the beam and in front of that

install

> a half waveplate to allow you to select the ratio of power between
> the two paths? This seems more robust for general use in my opinion.
>
> Best regards,
> Josh
>
> On Thu, Jul 30, 2015 at 12:25 AM, Kyle Douglass <[hidden email]>
> wrote:
>
> > *****
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> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
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posting.
> > *****
> >
> > Hello everyone,
> >
> > In my lab we have two microscope setups in two different rooms
separated
> > by a hallway between them. One of our microscopes has a free-space
laser
> > that must remain in place; however, I would like to use this laser
with the
> > microscope located in the other room while maintaining its ability to
be
> > used with its current microscope. Both microscopes accept free-space
beams
> > as inputs for fluorescence microscopy in an epi-illumination geometry.
> >
> > I am considering the following solution: introduce a flipper mirror
before
> > the fixed laser to allow me to switch between a path that would send
the
> > beam into its current microscope and another path that would couple
the
> > beam into a long multi-mode fiber. I would then run the fiber above
the
> > ceiling panels between the labs and onto the table of the other setup,
> > where the output light would be collimated and introduced like normal
into
> > the other microscope. I do not require a single-mode beam for the
second
> > microscope. In fact, I am proposing to use a multi-mode beam to
achieve a
> > better power coupling efficiency into the fiber and to prevent burning
the
> > fiber cladding by allowing for larger focal spot sizes when coupling.
I
> > also am not concerned about the speckle on the sample since I am
averaging
> > over multiple speckle patterns during the acquisition of a single
frame.
> >
> > My primary concern is the stability of the input and output couplers.
The
> > microscopes are used by people with little optics experience and this
> > solution must be as easy as possible to switch between the two paths.
> > Ideally, the only action required would be to flip the mirror up or
down
> > (after the initial alignment, of course).
> >
> > Here are my questions:
> > 1. Has anyone tried such an approach with satisfactory results and
would
> > be willing to comment?
> > 2. Would vibration of the fiber significantly affect its propagation
> > direction upon leaving the output coupler?
> > 3. Would a "standard" flipper mirror or magnetic mount have sufficient
> > return accuracy to avoid having to adjust the input coupler alignment
every

> > time we switched between microscopes?
> > 4. Is there another obvious solution I am missing?
> >
> > Thanks for the responses!
> > Kyle
> >
> > --
> > Kyle M. Douglass, PhD
> > Post-doctoral researcher
> > The Laboratory of Experimental Biophysics
> > EPFL, Lausanne, Switzerland
> > http://kmdouglass.github.io
> > http://leb.epfl.ch
> >
>
> --
> Joshua C. Vaughan
> Assistant Professor
> Department of Chemistry
> Box 351700
> University of Washington
> Seattle, WA 98195
> 206-543-4644

Prof. Sudipta Maiti
Dept. of Chemical Sciences
Tata Institute of Fundamental Research
Homi Bhabha Road, Colaba
Mumbai 400005, India
Ph. [phone]
Alternate e-mail: [hidden email]
webpage: biophotonics.co.in