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An AOD (as used in the old Noran systems) is highly chromatic and so cannot be used in fluorescence.  AOD based fluorescence systems (Lasertek, Noran) have used  the equivalent of slit, rather than spot, detection.  

                                                                        Guy

-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Smith, Benjamin E.
Sent: Saturday, 6 July 2013 12:14 AM
To: [log in to unmask]
Subject: Re: AOD v Resonant scanner

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Hey Gary,
   We have the resonant scanner installed on our Leica SP8, and it certainly has some ups and downs:

Pros:
    Video scan rates (8000 Hz)
    No discernible image distortion
    Zooms to 48x
    Pairs well with hybrid detectors (in line accumulate mode)
    Can be used with a pinhole aperture, resulting in higher axial resolution
   
Cons:
    High pitched frequency noise emitted form the scanner (which gets louder at lower zoom = larger amplitude)
    The scanner lasts about 4-6 hours at its lowest zoom (1.25x) before giving an error and shutting down.
    We couldn't ever get the bidirectional scan phase to line up perfectly (although we got it close)
    No frequency control, you are stuck at the resonant frequency of the scanner
    Lots of shot noise in live scan mode (although all high speed scanners would have this).

Another thing to consider is I've known AOTFs to burn out over time, but have not yet had a galvanometer burn out, so I would imagine a resonant scanner would last much longer than an AOTF that is rapidly cycling through a frequency regime.  My guess is this, and the increased axial resolution, is why manufacturers stick with resonant scanners.

You can also find a good discussion on the challenges of various high speed scan technologies here: http://www.microscopyu.com/articles/confocal/resonantscanning.html

Hope this helps,
    Ben Smith
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From: Confocal Microscopy List [[log in to unmask]] on behalf of Laevsky, Gary S. [[log in to unmask]]
Sent: Friday, July 05, 2013 8:26 AM
To: [log in to unmask]
Subject: AOD v Resonant scanner

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Hi All,

This would be for a MP application, so descanning is not an issue.

I would think resonant galvos would be superior on the throughput side, whereas an AOD would win on speed and control (imagine, a trade-off).

Thanks in advance for your feedback.




Best,

Gary



Gary Laevsky, Ph.D.
Confocal Imaging Facility Manager
Dept. of Molecular Biology
Washington Rd.
Princeton University
Princeton, New Jersey, 08544-1014
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