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To answer your question directly, there is no information beyond the  
highest spatial frequency contained in the PSF.  The power spectrum  
does not fall to zero at the diffraction limit but rolls off very  
rapidly. Noise then limits further extraction of information from  
these higher frequencies.

Hope this helps

Mark


On 15/04/2011, at 8:41 AM, Martin Wessendorf wrote:

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>
> On 4/14/2011 3:31 PM, Mark Cannell wrote:
>
>> I'm afraid the idea is MUCH older than 2008. I recall reading a paper
>> from the (?) 1960's that discussed the idea that the diffraction  
>> limit
>> was not a real limit at all. I believe they were using bacteria as an
>> example of where knowledge of the object imparts more information to
>> overcome the 'limit'
>
> I think no one would deny that if you know what you're looking at,  
> you can break the "resolution barrier"--STORM and PALM being prime  
> examples.  However, I'd still be interested in hearing whether-- 
> without having any additional information about the sample--there is  
> any theoretical limit to resolution in fluorescence microscopy,  
> other than that imposed by signal-to-noise ratio.
>
> Martin
> -- 
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