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Thanks for all the information... Much appreciated!
Regards,
Jason
----------------------------------------------------------
Dr Jason Goh
School of Electrical & Electronic Eng.
University of Nottingham
TEL: +44 (0) 115 951 5556
FAX: +44 (0) 115 951 5616
>>> [log in to unmask] 11/18/03 11:41am >>>
Search the CONFOCAL archive at
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Dear Janson,
The virtual state in the 2P absorption is not so spectrally defined. For
FITC you can have a good signal starting at 790 nm. The absorption
spectrum dependents a lot with the fluorofore and its much more wide
than 1P.
Here you can find some 2P absorption spectra
http://microscopy.bio-rad.com/products/multiphoton/Radiance2100MP/mpspectra.htm
All the best,
Nuno Moreno
Jason Goh wrote:
> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> Hi all,
>
> At the moment I'm designing a variant on a two-photon fluorescence microscope and as an optical engineer, have a question on a practical aspect of the operation.
>
> I'll be using fluorescein (FITC - excitation peak 494nm) as my fluorophore which would suggest a two-photon excitation wavelength of 988nm. In the literature, I've not seen anyone use an excitation wavelength this high - mainly seems to be <800nm. Is there any practical reason for this? Is it due to decreased laser efficiency outside the optimum running wavelength (approx. 800nm). I would have thought it was always best to operate at the excitation peak of the fluorophore to get more emission for the same amount of incident power...
>
> Thanks in advance for your help,
> Jason
>
> ----------------------------------------------------------
> Dr Jason Goh
> School of Electrical & Electronic Eng.
> University of Nottingham
> TEL: +44 (0) 115 951 5556
> FAX: +44 (0) 115 951 5616
>
--
___________________________
Nuno Moreno
Phone: +351 214464606
Fax : +351 214407970
www.igc.gulbenkian.pt
Cell Imaging Unit
Instituto Gulbenkian de Ciência
Portugal
___________________________
