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I feel your pain!  I have a pair of prisms in my compressor.  Whenever I
change my Ti:Saph's wavelength I have to realign the prisms.  The automated
systems like the Deepsee and Vision  do this for you, but they are
expensive.  One trick I am currently working on is overcompensating with
chirped mirrors, then using glass wedges to bring the pulse back into
optimum.  If I put the wedges on a translation stage it is a simple matter
to slide a wedge in and out of the beam path.  It would only be a single
adjustment, and I can mark the micrometer which moves the wedge for
different wavelengths.  I am going to have a set of wedges custom-designed
for Ti:Saph lasers.  I had great success with this for my prism compressor.
 I got a company to cut and anti-reflection coat them to my design; I plan
on having the same thing done for the wedges.  Since we're talking about it,
would anyone be interested in a positive-dispersion-control pair of glass
wedges designed for Ti:Saph lasers?  The more the company produces for me in
a batch the cheaper they are individually.  If anyone wants to get on-board
give me an email; prices will probably be under $1000 for two wedges with AR
coatings and angles optimized for Ti:Saph lasers.  You put the two wedges
into a beam and move one or both back and forth.  This does not deviate the
beam and allows you to put controlled amounts of glass (I'm probably going
with fused silica) into the beam.  This lets you put controlled amounts of
positive dispersion on the beam to counteract an excess of negative from
your chirped mirrors or whatever you are using.

Craig


On Sat, Jul 9, 2011 at 1:26 PM, Stanislav Vitha <[log in to unmask]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Craig,
> We use a pair of chirp mirrors, typically set-up with 7 or 8 pairs of
> bounces
> (depends on the objective used). We slightly over-compensate and have
> several mm of BK7 glass in the laser path, that we can take out as needed
> for
> deep imaging.
> The slight downside of the current set up is that changing the number of
> bounces on the chirp mirrors requires laser re-alignment.
>
>
> Stan
>
>
> On Fri, 8 Jul 2011 14:32:40 -0600, Craig Brideau <[log in to unmask]>
> wrote:
>
> >*****
> >
> >Actually the Chameleon was designed for 140fs pulses for this reason.  For
> a
> >'typical' microscope system, transform-limited 140 fs gives you minimum
> >dispersion.  On the other hand, if you have a pulse compressor you want to
> >start with as short a pulse as possible as the compressor can keep
> >dispersion in check for you.
> >If I might ask, Stan, what do you use for a compressor on your 10fs laser?
> >
> >Craig
> >
> >
> >On Fri, Jul 8, 2011 at 1:57 PM, Stanislav Vitha <[log in to unmask]>
> wrote:
> >
> >> *****
> >> To join, leave or search the confocal microscopy listserv, go to:
> >> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> >> *****
> >>
> >> Also, it depends on the pulse width.
> >> the shorter the pulse, the more you may need the dispersion control as
> you
> >> go
> >> deeper in the sample.
> >> On our system with 10 fs pulses, we really cannot live without pre-chirp
> >> (dispersion control). Your standard oscillator (~100-fs pulses?) is much
> >> more
> >> forgiving.
> >>
> >> Stan Vitha
> >> Microscopy and Imaging Center
> >> Texas A&M University
> >>
>