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Hm, I should have drawn the rays differently between the annular aperture
and the condenser lens in the phase contrast illustration. Oops.

I think this is irrelevant to my questions, though. Hope it's not a
distraction.
On Mar 26, 2014 3:59 PM, "Andrew York" <
[log in to unmask]> wrote:

> Some excellent points have been raised:
> * Deflection and optical path length differences are often two sides of
> the same coin (Zdenek)
> * Image brightness in phase microscopy is sensitive to reflection, in
> addition to absorption and deflection (James)
> ...and I'm not sure we've reached a consensus on my original question.
>
>  I've tried to illustrate the simplest realistic case which addresses my
> question and avoids these complications. In the diagram below:
> http://goo.gl/2u6DDe
> ...my phase object is a homogenous glass slab with two raised regions. The
> two regions have different thicknesses, (let's say 200 nm and 400 nm
> thick). The two raised regions are wide compared to the lateral resolution
> of the imaging system (let's say tens of microns). The raised regions are
> perfectly smooth, with the same index of refraction as the slab. The
> immersion medium is air. The illumination wavelength is visible (let's say
> 500 nm).
>
> My expectations:
> The phase contrast image shows the same brightness everywhere in the
> image, except at the edges of the raised regions.
> The interferometric image shows a brightness which depends on the local
> thickness of the object, three different brightnesses in this case.
>
>  I believe Zdenek and Shalin share my expectations. I sounds like Tobias
> does not share my expectations, but is equally curious about the answer.
> James, what's your expectation?
>
> My questions:
> 1. Do my expectations match reality?
> 2. Is there any confusion or disagreement about what to expect?
> 3. Does anyone think the phase contrast image intensity near the centers
> of the raised regions shows which of the two regions is thicker?
>
> Bonus questions: (Assuming 1, 2, and 3 are straightforward)
> 4. Does varying the phase shift induced by the phase ring (as described by
> Phillippe) allow image intensity near the centers of the raised regions to
> tell us local thickness of the raised regions?
>
> On Wed, Mar 26, 2014 at 11:01 AM, MODEL, MICHAEL <[log in to unmask]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
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>> *****
>>
>> Sergey -
>> Quantitative DIC has been described in
>>
>> Kou et al. "Transport-of-intensity approach to differential interference
>> contrast (TI-DIC) microscopy for quantitative phase imaging." Optics
>> letters 35.3 (2010): 447-449.
>>
>> For quantitative brightfield also look for "transport of intensity".
>>
>> There is also a method called "defocusing microscopy", I don't know much
>> about it.
>>
>> Mike
>>
>> -----Original Message-----
>> From: Confocal Microscopy List [mailto:[log in to unmask]]
>> On Behalf Of Sergey Tauger
>> Sent: Wednesday, March 26, 2014 10:45 AM
>> To: [log in to unmask]
>> Subject: Re: Phase contrast microscopy
>>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
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>> *****
>>
>> Hi,
>>
>> Mike, Phillippe, could you please share the article names of quantitative
>> phase contrast, brightfield and DIC? I cannot find any articles neither
>> that prove the methods are quantitative, nor PSF for the methods.
>>
>> Best,
>> Sergey
>>
>
>