http://confocal-microscopy-list.275.s1.nabble.com/Re-SHG-tp592071p592075.html
Not necessarily. Best to confirm with a polarizer that you're getting out
the same as what you put in. As far as I know it is possible to get out a
> Search the CONFOCAL archive at
>
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal>
> Dear Craig,
>
> Thank you very much for the information.
>
> I aligned the crystal and I got the blue beam and I block the 2p with
> the filter.I didn't use any polarizer in the path.is it possible that
> I am not getting the highest value and I should use the polarizer or
> once I get the blue it means that my laser beam is polarized in the
> same way of the crystal and I don't need to try waveplate?
>
> Thanks
> Sarah
>
> On Thu, May 8, 2008 at 1:10 AM, Craig Brideau <
[hidden email]>
> wrote:
>> Search the CONFOCAL archive at
>>
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal I've interspersed
>> a
>> few of my own comments below:
>>
>> >
>> > You have to make sure you carefully filter the remaining of the Ti:Sa
>> laser after doubling, so you won't have 2P events
>> > as well.
>>
>> Typically a good short pass filter centered at 600 or 650 will do the
>> job.
>> Keep it at right-angles to the beam.
>>
>> >
>> > If the doubling crystal is your own "home built" addition, you don't
>> > place
>> it in the Ti:Sa cavity but rather after it.
>> >
>>
>> Yeah, a doubling crystal in the cavity will potentially wreck the laser
>> if
>> it's not built for it.
>>
>> > I guess you're using a BBO or LBO, in which case a 5mm by 5mm
>> > piece will be enough, coming to it at a tight focus.
>>
>> Typically you get a very thin slip of crystal, almost like a microscope
>> cover slip. Normally this comes mounted in a 1" metal circle or some
>> 'frame' that you can place in an optical mount.
>>
>> >
>> > Finding the "mismatch" axis and aligning it is a bit tricky and
>> > requires 6
>> degrees of freedom (x-y-z rotational and angular).
>>
>> If you have a 1/2 waveplate to rotate the polarization of your laser it
>> takes one degree of freedom out of the equation (or that is to say
>> transfers
>> it to the waveplate, which is simple to rotate). In the case of the
>> waveplate you want to rotate it around the optical axis. That is to say
>> pretend your laser beam is an axle and the waveplate is a wheel rotating
>> around it. Adjust the polarization of your laser beam such that it is
>> perpendicular to the table surface. If you are very lucky your laser
>> might
>> already be this way naturally. This means you might be able to get away
>> without the waveplate. The crystal, on the other hand, you want to first
>> align so that it's preferred polarization is the same as the laser, i.e.
>> perpendicular to the table if that's the laser's polarization (or you
>> made
>> it that way with the waveplate). Usually there's a mark for this on the
>> crystal mount/frame. You then want to turn the crystal on an axis which
>> is
>> also perpendicular to the table. Thorlabs and Newport both carry
>> appropriate mounts for doing this sort of thing. Again, the crystal
>> manufacturers, or even the technical support guys at Thor or Newport, can
>> generally help you out. Once you get SHG just gently play with all the
>> degrees of freedom until you get a maximum. Measure the power after the
>> short pass filter and seek the highest value.
>>
>> Craig
>>
>>
>>
>> >
>> >
>> >
>> > Hope this helped- good luck,
>> >
>> > Eli
>> >
>> >
>> > 6 degreess
>> >
>> >
>> >
>> >
>> >
>> > ---- Original message ----
>> > >Date: Thu, 8 May 2008 09:34:58 +0800
>> > >From: Peng Xi <
[hidden email]>
>> > >Subject: Re: SHG
>> > >To:
[hidden email]
>> > >
>> > >Search the CONFOCAL archive at
>> > >
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal>> > >
>> > >Hi Sarah,
>> > > Just like you asked, it will be an one-photon excitation. So,
>> > >although it is possible that you create a femtosecond 400nm laser
>> > >pulse,
>> > >it is still linear excitation -- one photon process. Thank you!
>> > > I am very interested in the experiment itself -- have you tried to
>> > >put a SHG crystal inside the Ti:Sa laser cavity and see the 400nm
>> emission?
>> > >
>> > >Best regards,
>> > >Peng Xi
>> > >Associate Professor
>> > >Institute for Laser Medicine and Biophotonics
>> > >Shanghai Jiao Tong University
>> > >800 Dongchuan Rd.
>> > >Shanghai 200240, China
>> > >Tel: (86) 21-3420-4076
>> > >
http://biophotonics.sjtu.edu.cn/>> > >
>> > >
>> > >
>> > >Sarah Kefayati wrote:
>> > >> Search the CONFOCAL archive at
>> > >>
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal>> > >> Hello all,
>> > >>
>> > >> I appreciate if you could help me with my question:
>> > >>
>> > >> I just want to make sure about this fact that by using a non-linear
>> > >> crystal in the path of my Ti-sapphire laser I will have the
>> > >> frequency
>> > >> doubled beam which excites my sample via traditional one-photon
>> > >> excitation.
>> > >> But dose the intensity of the emitted fluorescence depend on
>> > >> excitation power linearly or quadratically?
>> > >>
>> > >> any information in this regard is highly appreciated.
>> > >>
>> > >> Thanks
>> > >> Sarah
>> > ________________________________
>> > Eli Rothenberg, Ph.D.
>> > Post Doctoral Research Associate,
>> > Howard Hughes Medical Institute,
>> > Department of Physics,
>> > University of Illinois,
>> > Urbana-Champaign. 61801.
>> > Illinois, USA
>> > Tel: +217-333-3393;
>> > Fax: +217-244-7187;
>> > Email:
[hidden email]
>> >
>>
>>