pre-chirping

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Jerry Sedgewick Jerry Sedgewick
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pre-chirping

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I am interested in setting up pre-chirping in the laser path going to a
custom built multiphoton. I have been searching in vain for exact
information on the components. I bought the prisms, but I am uncertain
about the first mirror that directs the laser to the prisms (and then
allows the returning, reflected laser to pass through), and the second
mirror. My guess is that the first mirror must be a linear polarizer, or a
polarizer that separates the s and p polarization. The second mirror must
be a grating of some sort that re-polarizes the laser so that it passes
through the first mirror.

Rather than guessing, it would make my day if I could get specifics on the
mirrors.

Thanks!

Jerry Sedgewick
Tong Ye Tong Ye
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Re: pre-chirping

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Please check an application note (AppsNote29.pdf) at Newport website:
http://www.newport.com/store/genproduct.aspx?id=168496&lang=1033&Section=Dow
nloads
Thanks Newport TAC.

Tong Ye, Ph.D.
Assistant Research Professor
Department of Chemistry
Duke University,
Box 90346
Durham, NC 27708-0346

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On
Behalf Of Jerry Sedgewick
Sent: Wednesday, August 29, 2007 4:01 PM
To: [hidden email]
Subject: pre-chirping

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

I am interested in setting up pre-chirping in the laser path going to a
custom built multiphoton. I have been searching in vain for exact
information on the components. I bought the prisms, but I am uncertain
about the first mirror that directs the laser to the prisms (and then
allows the returning, reflected laser to pass through), and the second
mirror. My guess is that the first mirror must be a linear polarizer, or a
polarizer that separates the s and p polarization. The second mirror must
be a grating of some sort that re-polarizes the laser so that it passes
through the first mirror.

Rather than guessing, it would make my day if I could get specifics on the
mirrors.

Thanks!

Jerry Sedgewick
Mark Cannell Mark Cannell
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Re: pre-chirping

In reply to this post by Jerry Sedgewick
Search the CONFOCAL archive at
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Hi Gerry

The typical path using 2 prisms is via a small mirror into the first
prism (we set this at minimum at minimum deviation but this can be
changed to alter chirp). Then to the second prism (at minimum devation
to produce a collimated horizontally spread spectrum), and then two
mirrors to reflect the light back and displace the beam vertically which
then passes back through the second and first prisms respectively. After
the beam has left the first prism, note the beam has been displaced
vertically is and thereby separated from the input beam.

BUT are you sure you need to do this? If the input pulse is ~120 fs the
pulse broadening is quite minor. We used a pair of gold mirrors to to
return and displace the beam but if you have 1" fs mirrors they would
work as well.

For typical prism spacing see:

Soeller, C. & Cannell, M.B. (1996) Construction of a two-photon
microscope and optimisation of  illumination pulse width. _Pflugers
Archiv_ 432: 555-561.

Cheers Mark

Jerry Sedgewick wrote:

> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> I am interested in setting up pre-chirping in the laser path going to
> a custom built multiphoton. I have been searching in vain for exact
> information on the components. I bought the prisms, but I am uncertain
> about the first mirror that directs the laser to the prisms (and then
> allows the returning, reflected laser to pass through), and the second
> mirror. My guess is that the first mirror must be a linear polarizer,
> or a polarizer that separates the s and p polarization. The second
> mirror must be a grating of some sort that re-polarizes the laser so
> that it passes through the first mirror.
>
> Rather than guessing, it would make my day if I could get specifics on
> the mirrors.
>
> Thanks!
>
> Jerry Sedgewick
Craig Brideau Craig Brideau
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Re: pre-chirping

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Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Typically the chirp from an average microscopy setup is not enough to
greatly diminish image quality.  If you are working with weaker samples or
otherwise have borderline performance then you may want to try
pre-compensation.  Otherwise, the complexity and table space involved in
setting up a compressor is probably not worth it.