*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Hi Andrew,

as far as I recall my studies of canonical and second quantisation, you are 
right. Unfortunately.
There are some particular problems that can be solved very efficiently using
second quantisation, but trying to solve practical problems I've always 
ended up in messy math... (that's why I gave up solid state physics and 
turned to optics in the first place...)
I can't see the benefits the QED can bring to our "first degree" optics. 
Actually we can greatly simplify the matter by separating the particle- and 
wave- aspects of light. That means we can resort to solving 'simple' Maxwell
equations and add Poisson's 'salt and pepper' to the result :-).
I would stick to that.

Regards,
zdenek svindrych



---------- Původní zpráva ----------
Od: Andrew York <[log in to unmask]>
Komu: [log in to unmask]
Datum: 24. 3. 2014 22:19:42
Předmět: Re: phase contrast microscopy

"*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Please correct me if I'm wrong, but I believe using QED to describe light
propagation ends up looking an awful lot like using wave optics, except
you're allowed to have non-classical states of light (non-coherent states).
Practically, the math only gets harder, the concepts are strictly less
intuitive, and you still end up with a bunch of oscillatory integrals,
which are numerically hellacious.

I'd be happy to be wrong about this one, but that's what I've taken away
from my studies of optics and QED. A great way to prove me wrong would be a
simple problem worked with both approaches, showing the same result more
clearly or with less effort using QED.


On Fri, Mar 21, 2014 at 10:37 AM, Daniel White <[log in to unmask]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> >I tried to construct a more intuitive (non-Fourier) diffraction model
> >of phase-contrast using Huygen's wavelets, but didn't get very far.
>
> >Shalin
>
> How about forgetting the waves idea,
> Which gets complicated very quickly...
> And instead use Feynman's quantum electrodynamics approach. Or plainly 
put,
> probability. That's how light, photons, really works. Waves are just a
> clunky approximation.
>
> Is there a way to calculate probability amplitudes in phase contrast?
>
> From that point of view light goes everywhere it can, whenever it can, 
with
> the same probability amplitude, and no need for complex ray or wave optics
> to describe it.
>
> The net effect of the probability amplitudes of all possible paths with
> their spinning components, all adding up will lead to the phase image. 
Then
> we see why optical path lengths are involved in also describing the
> contributions of scattered or diffracted rays?
>
> See YouTube videos of Feynman describing QED, the fits of light, in new
> Zealand in the 70s. The second lecture us particularly illuminating (boom
> boom!!!)
>
> Best
>
> Dan
>"