How many photons in one airy disc?
jayz
In a single airy disc, how many photons approximately could it be
composed of??
In a parallel light rays coming from distance point to the objective
lens, how many photon(s) are there and what's the distribution??
Basically. What is the relationship between photons and light rays
in telescope optics??
Thanks.
jayz
Chris L Peterson
>In a single airy disc, how many photons approximately could it be
>composed of??
The intensity of the Airy disk is determined by the photon flux
(photons/second), which is dependent on both the aperture of the
telescope and the intensity of the source. An accurate calculation would
also consider atmospheric losses and optical losses, although these are
relatively small.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
EP Guy
"jayz" <jaydu...@yahoo.com> wrote in message
news:1138538961.6...@f14g2000cwb.googlegroups.com...
why do you ask?
jayz
I've been following the debates of the Afshar experiment in which
Bohr Quantum Complementary Principle is allegedly disproven.
Some think there is a flaw in his experiment. The debates is
still ongoing. See the following link:
http://www.sciencefriday.com/images/shows/2004/073004/AfsharExperimentSmall.jpg
(press the magnify icon to enlarge)
http://motls.blogspot.com/2004/11/violation-of-complementarity.html
http://irims.org/blog/index.php/2005/03/13/questions_welcome_1#comments
http://users.rowan.edu/~afshar/
http://en.wikipedia.org/wiki/Afshar_experiment
In the first url illustration. The double slit uses a lens. So I was
tracing
what should have happened to each photon from the source or its
path and the connection with the light rays. In light rays, there
are many photons moving within one light ray in random, right?
or does one light ray represent one photon?? In QM, they talk
about fields, wave, particle and I'm trying to see what is the
relevance or connection to light ray in telescope with regards
to them. What do you (or others) think? Note Afshar experiment
puts diffraction grating in the lens so telescope guys should
be more familiar with the aberrations it should cause.
jayz
Salmon Egg
1138538961.6...@f14g2000cwb.googlegroups.com, "jayz"
<jaydu...@yahoo.com> wrote:
382,395,295,2116.43.
They more or less travel t6he same path.
Bill
-- Ferme le Bush
jayz
Ok. So a light ray is composed of numerous photons travelling in the
same
path.
Now refer to this image:
http://www.sciencefriday.com/images/shows/2004/073004/AfsharExperimentSmall.jpg
(use magnify to enlarge)
So it's clear the the behavior of light as wave and particle can be
detected
at the same time violating the principle of complementary in quantum
mechanics enough to cause the "Quantum Bombshell" headlines in
http://www.newscientist.com/article.ns?id=mg18324575.300
But a detractor says something is wrong with his analysis.
http://motls.blogspot.com/2004/11/violation-of-complementarity.html
Now. reading It. I think Lubos doesn't understand that as each
light ray hit the lens, it converge into an airy disc so each photon
that doesn't pass thru the wires is still affected by the wires since
the detector detects a particular airy disc (composed of all the
photons in one light ray) and not a single photon, right?? So
Lubos is wrong? sci.physics dudes agree Lubos is
right. But maybe you opticians and telescope airy discers
can analyze better and decide if a century old principle in Quantum
Mechanics is violated or not.
jayz
Chris L Peterson
>Ok. So a light ray is composed of numerous photons travelling in the
>same
>path.
There is no such thing as a "light ray". It is a geometrical construct,
useful for analysis. Whether you treat light as a wave or particle
phenomenon doesn't change this. A ray has no physicality.
In reality, each photon is in its own path; no two will be in exactly
the same one. You could certainly treat the path taken by any individual
photon as a ray from a geometrical analysis standpoint.
Jürgen Appel
>>Ok. So a light ray is composed of numerous photons travelling in the
>>same
>>path.
>
> There is no such thing as a "light ray". It is a geometrical construct,
> useful for analysis. Whether you treat light as a wave or particle
> phenomenon doesn't change this. A ray has no physicality.
>
> In reality, each photon is in its own path; no two will be in exactly
> the same one.
That is not right.
Photons are excitations of the electromagnetical field modes. Of course it
is possible, that a particular field mode contains multiple energy quanta
(photons). In fact, this is almost always the case, as it is quite
challenging to prepare Light states where the number of Energy quanta in a
particular mode is a well defined number (so called Fock states). Thermal
light states and coherent light coming from a laser do not have a well
defined number of energy quanta in them.
What you probably mean is, that a photon does not have to be localized. As
modes of the electromagnetic field can be pretty spread out in spacetime
(monochromatic plane wave modes have an infinite width and lenght), having
1 photon in such a mode does not tell you anything _where_ it is located.
Best regards,
Jürgen
--
GPG key:
http://pgp.mit.edu:11371/pks/lookup?search=J%FCrgen+Appel&op=get
Louis Boyd
Electromagnetic waves manifest themselves as photons when they interact
with a detector, be it film, ccd, photomultiplier, or the retina of an
eye. Wave descriptions are generally better for describing how light
energy propagates though space while photons are better for describing
how how light behaves in energy conversion. Both waves and photons are
correct but incomplete descriptions of the same phenomina.
I'm an engineer, not a physicist. This destinction may be simplistic or
dead wrong but it works for me.
--
Lou Boyd
Fairborn Observatory
Chris L Peterson
<jap...@linux01.gwdg.de> wrote:
>What you probably mean is, that a photon does not have to be localized.
I agree with that, but it isn't what I meant, which was that there is no
such thing as a "ray" consisting of a stream of photons, because no two
photons will be in exactly the same path. I suppose you could create
some definition of ray that included a non-zero width (radius), and the
resulting finite volume could be seen as containing a stream of photons.
But I can't think of any particularly useful reason for doing that.
My sense was that the OP was viewing a ray as if it were some sort of
physical entity.
Jürgen Appel
> I've been following the debates of the Afshar experiment in which
> Bohr Quantum Complementary Principle is allegedly disproven.
> Some think there is a flaw in his experiment. The debates is
> still ongoing. See the following link:
>
>
http://www.sciencefriday.com/images/shows/2004/073004/AfsharExperimentSmall.jpg
> (press the magnify icon to enlarge)
I do not see the point that this experiment makes in respect to quantum
mechanics. The same experimental outcome would have been predicted by
Maxwell >50 years before quentum mechanic was invented. It is all
classical electrodynamics.
Photons are excitations of the electromagnetic field modes.
So you calculate the field modes and find that the wires are placed in the
dark fringes of the diffraction patterns. Whether the energy in each of
these modes is quantized or not does not make a difference to the
experimental outcome.
> In the first url illustration. The double slit uses a lens. So I was
> tracing
> what should have happened to each photon from the source or its
> path and the connection with the light rays.
The purpose of the lens is just to collect all light that passes the
grating and image each pinhole onto the according CCD.
> In light rays, there
> are many photons moving within one light ray in random, right?
Not really. You are only allowed to talk about rays, if the dimensions of
the experimental apparatus are huge compared to the wavelength. Then wave
optics can be approximated by ray optics. This is not the case in this
experiment -> You have to use wave optics.
In wave optics you solve the time independent wave equations with certain
boundary conditions set by the experiment (e.g. Field strength=0 on the
entry stop, non-zero in the apartures,...)
The solutions you will find there are the electromagnetic field modes of
your system. Your laser excites each of these solutions to a certain
extend. This was more or less the state of science before Quantum
Mechanics.
Quantum mechanics now states, that the energy stored in each of these
excitations comes in Portions, the so-called quanta. These are the
photons.
If you think of it like this it will not be very surprising, that once you
excite one electromagnetic field mode (putting a photon into it), it can
only be found where that particular field mode shows a nonvanishing field
strength. I.e. you will never find this photon hitting the wire, since
that mode vanishes there (this follows from the diffraction-pattern of a
double slit).
However, since each field mode extends over _both_ slits, it does not come
as a surprise either, that the image changes if you put an absorber in
front of one slit.
So for me as a physicist doing quantum optics this experiment does not come
surprising at all. It's rather more surprising why people think of photons
again and again as particles _or_ waves. They are neither. It's like a can
of coke which looks like either a rectangle or a circle only if you look
at it from particular directions. In general it looks quite different...
Greetings,
Phil Hobbs
> Electromagnetic waves manifest themselves as photons when they interact
> with a detector, be it film, ccd, photomultiplier, or the retina of an
> eye. Wave descriptions are generally better for describing how light
> energy propagates though space while photons are better for describing
> how how light behaves in energy conversion. Both waves and photons are
> correct but incomplete descriptions of the same phenomina.
>
> I'm an engineer, not a physicist. This destinction may be simplistic or
> dead wrong but it works for me.
From an engineering viewpoint, this is exactly right. You can't
consistently think of a beam of light as being "composed" of photons in the
way that a waterfall is composed of water molecules, and Maxwell's equations
are the relativistically and quantum-mechanically correct description of
light propagation in vacuo, at any reachable intensity level. Any reasoning
that begins with "there was this photon, see, and it went round the optical
system this way..." is doomed from the outset.
A couple of years back the Optical Society of America's house organ, *Optics
and Photonics News* issued a supplement in which several well-respected
optical physicists attempted to answer the question "What is a photon?"
They all had firm opinions, backed up by clear reasoning, but in the end very
little agreement resulted. Certainty on that point appears to be restricted
to amateurs.
Cheers,
Phil Hobbs
jayz
Maybe it's this.
The photons in one light ray has the same angle. They converge
into a cone ending as airy disc. So an airy disc has all the photons
in the parallel rays converging into it. Disagree? It has to do with
angle. Now in a second ray of light, the photons path has another
angle This is why the airy disc of two light ray can be beside
each other.
jayz
Chris L Peterson
>Maybe it's this.
>
>The photons in one light ray has the same angle. They converge
>into a cone ending as airy disc. So an airy disc has all the photons
>in the parallel rays converging into it. Disagree? It has to do with
>angle. Now in a second ray of light, the photons path has another
>angle This is why the airy disc of two light ray can be beside
>each other.
You'd do best not thinking of this in terms of rays. Rays are a useful
fiction for analyzing optics geometrically, but when you are talking
about Airy disks, diffraction is involved, and geometric optics is no
longer the model to use.
A star essentially represents a point source to an optical system. It is
sending out photons in all directions, and the telescope intercepts some
very small fraction. The number intercepted depends on the aperture of
the scope (and the brightness of the star). Because the star is
equivalent to a point source at infinity, all the photons from it that
enter the telescope are traveling parallel to each other- but none are
following exactly the same path. The optics bring nearly all of these
photons to focus in a small area. The exact profile of that area is
determined by diffraction- something that occurs because the aperture is
of finite diameter.
nick
If the number is of interest, Schroeder gives (Astronomical Optics
1st ed. p188) entering photon flux as P=1000 photons/(sec cm^2 A)
for a zero magnitude star at 0.55u wavelength. Average number of
photons within the Airy disc is given by N=etP, "e" being the energy
portion contained within the Airy disc (0.838 for perfect wavefront)
and
"t" the transmission coefficient. A 2.4m f/24 Hubble w/33% linear c.o.
(e~0.65) and ~0.8 transmission would place ~4.2 photons/sec into
the Airy disc for a 25th magnitude star and 2000A (Angstrom)
passband centered at 0.55u (microns).
The relation is no relation. Rays are geometrical abstraction with no
inherent ties to the actual force field. Photons are a model
abstraction
themselves. Simply put, light act as if it contains quanta of energy
(photons). No one really can tell what their actaulity - if any - is.
Vlad
Fan-o
ask 'how many seconds in a show '. What show!?
Fan-o
Chris L Peterson wrote:
> On 29 Jan 2006 15:43:05 -0800, "jayz" <jaydu...@yahoo.com> wrote:
>
> >Ok. So a light ray is composed of numerous photons travelling in the
> >same
> >path.
>
> There is no such thing as a "light ray".
Oh yes there is! Walmart has five for sale!
Fan-o
Chris L Peterson wrote:
> On 29 Jan 2006 15:43:05 -0800, "jayz" <jaydu...@yahoo.com> wrote:
>
> >Ok. So a light ray is composed of numerous photons travelling in the
> >same
> >path.
>
> There is no such thing as a "light ray". It is a geometrical construct,
> useful for analysis. Whether you treat light as a wave or particle
> phenomenon doesn't change this. A ray has no physicality.
>
> In reality, each photon is in its own path; no two will be in exactly
> the same one. You could certainly treat the path taken by any individual
> photon as a ray from a geometrical analysis standpoint.
Nope. sorry you c ant.
Fan-o
jayz wrote:
> > Chris L Peterson
> > Cloudbait Observatory
> > http://www.cloudbait.com
>
> Maybe it's this.
>
> The photons in one light ray has the same angle. They converge
> into a cone ending as airy disc. So an airy disc has all the photons
> in the parallel rays converging into it. Disagree? It has to do with
> angle. Now in a second ray of light, the photons path has another
> angle This is why the airy disc of two light ray can be beside
> each other.
>
> jayz
AsChris tried to tell you, "ray" is an imaginary geometrical construct to
help model (light and many other phenomina). You are trying to use "ray" as if
it had reality beyond its imaginary sense and efficacy beyond where it is
useful.
The concept of "ray" does not go very far in explaining the behavior of
light, especially at the quantum level. It would be like asking the concept of
"arrow" to explain your behavior viewing the dashboard dials in your car, as
you drive all day and go to the Post Office, Walmart, but not the Catholic
church on
Elm Street!
Every concept has a utility. "Ray" has a limited utility in this case.
Hope this helps -
qm
Fan-o
Louis Boyd wrote:
well. "Electromagnetic waves", if there is such a thing, do not
"manifest"
anything .... under any circumstance ... any more than they would
"manifest"
one thing when hitting a Bible vs another thing when hitting "Kama Sutra"!
What you said is very typical, but dead wrong.
Fan-o
Phil Hobbs wrote:
You mean there's something we dont know! I will have to tell FOX NEWS!
Martin Brown
> On 29 Jan 2006 15:43:05 -0800, "jayz" <jaydu...@yahoo.com> wrote:
>
>>Ok. So a light ray is composed of numerous photons travelling in the
>>same
>>path.
In quantum optics it would be closer to say that every individual photon
travels every possible path available to it and is detected at the
target according to its probability amplitude at the image plane.
> There is no such thing as a "light ray". It is a geometrical construct,
> useful for analysis. Whether you treat light as a wave or particle
> phenomenon doesn't change this. A ray has no physicality.
Although it has no physicality the definition of a light ray comes from
computing the shortest time for a ray leaving the source to reach a
given point on the detector. Fermats principle of least time. This
translates to a straight line in free space.
A light ray in classical geometrical optics is a shorthand for the
macroscopic case of finding the shortest time path between source and
object. The quantum treatment refines this by computing the phase
difference along all possible paths and as if by magic the bulk of the
probability amplitude for finding the photon cancels out except in the
vicinity of the classical ray path. The exact diffraction pattern
observed only depends on the shape of the aperture offered to the photon
along its path. Block some of these possible paths you affect the final
image (but block places where the probability amplitude is already zero
and you will have no effect at all).
It is an elegant experiment but it doesn't shed any new light.
>
> In reality, each photon is in its own path; no two will be in exactly
> the same one. You could certainly treat the path taken by any individual
> photon as a ray from a geometrical analysis standpoint.
And diffraction patterns would still be seen even if you reduced the
intensity to a point where there was only one photon in the apparatus at
any one time. The shape of the aperture that the photons must pass
through determines the diffraction pattern formed.
I don't see that the Afshar experiment has done anything unexpected.
When both slits are open the wires are on dark fringe nulls in a
sinusoidal probability distribution and so have no effect at all.
But when one slit is closed the wires are a brutal picket fence in the
way of light from the other slit (and do *not* exactly match the former
sinusoidal probability amplitude distribution). It is therefore no
surprise that the final image is affected.
Regards,
Martin Brown
jayz
photons are neither particles or waves as you say..
they also state the electrons are neither particles nor waves
In photoelectric effect a photon hits an electron like balls.
So they have characteristic of particles.
Now do you have any idea how each quanta is connected to
the field.. or the physical mechanisms.
For example. In particle accelerators, they can create particles
out of pure energy (by introducing kinetic energy to the lower
energy particles for example). The one trillion dollar question
is, question is.. what exactly occurs between the excitation of the
field and the creation of the particle.. like how did the field
precipitate the quanta (where is the characterisic of the spin,
charge, etc. stored in the field?).
It is because of this unknown that one can approximate photon
and electron as particles. Now in Afshar stuff. It is different
from all the other double slits because in the older setups,
everytime a particle or quanta is detected, the wave function
(or interference) collapsed. Some physicists believe in
the Many World Interpretation where each quanta path
is split to an infinite parallel realities. You see. This particle/wave
thing is still a valid puzzle. You can state subatomic particles
are neither particle or waves but one has to create the
causal mechanism by which a field can precipitate a quanta
with all the intrinsic properties and probabilistic quantum
characteristics. Isn't it that Feymann stated the double slit
is the only mystery of quantum mechanisms. It seems many
folks like engineers are desensitized and treat fields as another
nature unlike wave/particle. While true. It is still a mystery how
the field dynamics work. So those many quantum scientists
who debate about whether Copenhagen or Many World
Interpretations is true is still a valid thing (one only omit
this when one gets desensitized to the deeper aspect of
it).
Anyway. The following shares some background and mentions
the Transactional Interpretation which involves backward time contact.
http://www.analogsf.com/0409/altview2.shtml
You see. As long as the field dynamics of how quanta is
precipitated in step by step detail is not discovered (the
causal and hidden mechanism thing). Things like the
above is valid and so the Afshar debate continues (he is
presently writing a book about the Quantum Bombshell
that can put him in the history book along with Alain
Aspect, Bell, deBroglie, etc.).
jayz
jayz
You don't seem to get the essence of what Afshar is driving.
Since his detector can detect the photons coming from a
particular pinhole and *at the same wave* a wave charactistic
is detectred (by way of the wires not affected since it's in the
null zone hence implying the wave property). Then particle and
wave is detected at the same time.. which other double slits
experiments were not able to do. This is why it's a Quantum
Bombshell.
See (for briefing):
http://en.wikipedia.org/wiki/Afshar_experiment
http://www.analogsf.com/0409/altview2.shtml
jayz
jayz
Fan-o wrote:
> You keep using the term "light ray", which is meaningless. You might as well
> ask 'how many seconds in a show '. What show!?
>
When I talk about light ray. I'm referring to the photons path from
the distant object. Of course I know light is not a ray like a straight
line. But ok. I won't use the vague term light ray anymore.
jayz
Martin Brown
I see what he is saying, but I do not agree with his interpretation.
Image photon counting at high resolution also sees the effects of a
finite aperture despite counting individual photons. But they are not
measuring the complimentarity wave particle properties at exactly the
same time. The apparent Afshar conflict is in how it is being presented.
> Since his detector can detect the photons coming from a
> particular pinhole and *at the same wave* a wave charactistic
> is detectred (by way of the wires not affected since it's in the
> null zone hence implying the wave property). Then particle and
> wave is detected at the same time.. which other double slits
> experiments were not able to do. This is why it's a Quantum
> Bombshell.
>
> See (for briefing):
>
> http://en.wikipedia.org/wiki/Afshar_experiment
>
> http://www.analogsf.com/0409/altview2.shtml
When you make the measurement you see the particle at a position
determined by its probability amplitude. This is in turn a function of
all the paths that were available for it to travel from source to detector.
Classically the particle goes through one slit or the other but until it
finally reaches the detector we do not know which one. On its journey it
passes through the slits and the mesh of wires in a manner consistent
with quantum mechanics and forms a probability distribution consistent
with Youngs slits and the additional wire constraints.
So at the slit(s) and at the detector you have precise positional
information and at the "magic" grid of wires you have accurate momentum
(but no knowledge at all about the position). And in between these two
extremes you have a mixture satisfying Heisenbergs uncertainty
principle. Knowledge of the complementary variables is not simultaneous.
Knowing after the event that the photon seemed to come from one slit or
the other doesn't prevent wave interference effects occuring in transit.
Wave interference tells you the probability distribution of the photons
at the image plane - nothing in the Afshar experiment is unexpected.
Regards,
Martin Brown
Chris L Peterson
>> In reality, each photon is in its own path; no two will be in exactly
>> the same one. You could certainly treat the path taken by any individual
>> photon as a ray from a geometrical analysis standpoint.
>
>Nope. sorry you c ant.
In some ways, you can. Although an individual photon in flight can't be
localized, once that photon is detected its path can be determined in a
way that can be analytically useful. My point was only that this is
probably as close as you could come to defining a "ray" in any physical
way: based on the measured behavior of a single photon, not of a stream
of them.
Louis Boyd
It's easy to say I'm wrong. Please explain what is right.
jayz
What do you think is the part in QM Afshar didn't understand that
could have deceived him to claim he has disproven the principle of
complementary in quantum mechanics?
Are you familiar with quantum eraser.
http://en.wikipedia.org/wiki/Quantum_Eraser_Experiment
The experiment proved the principle of complementary in QM
is true... it described that when you knew the which way
path, the interference disappears. Why does this support
the Complementary Principle in contrast to Afshar which
doesn't appear to do it.
Tnx.
Jayz
EP Guy
"Chris L Peterson" <c...@alumni.caltech.edu> wrote in message
news:depqt1pdjn0q7jkue...@4ax.com...
> On Sun, 29 Jan 2006 17:48:43 -0700, Jürgen Appel
> <jap...@linux01.gwdg.de> wrote:
>
>>What you probably mean is, that a photon does not have to be localized.
>
> I agree with that, but it isn't what I meant, which was that there is no
> such thing as a "ray" consisting of a stream of photons, because no two
> photons will be in exactly the same path. I suppose you could create
> some definition of ray that included a non-zero width (radius), and the
> resulting finite volume could be seen as containing a stream of photons.
> But I can't think of any particularly useful reason for doing that.
>
> My sense was that the OP was viewing a ray as if it were some sort of
> physical entity.
Yeah like Death Ray in War of the Worlds...zzzzzzzzzttt!!!
OG
I was always a bit sceptical about Ashar's result. It seems to me that
although the photon detector purports to detect which pinhole is the source,
it does not actually tell us the path of any photon between pinhole and
detector.
Skywise
Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?
Salmon Egg
<in...@oblivion.nothing.com> wrote:
> This whole thread is reminding me of Ralph Sansbury.
You really screwed me up. I had completely forgotten about Ralph. I can only
hope that I can forget again.
Remember to forget Pearl Harbor.
Bill
-- Ferme le Bush
jayz
http://www.sciencefriday.com/images/shows/2004/073004/AfsharExperimentSmall.jpg
The outputs in the detector is a defocused image just like racking
the focuser in a telescope in and out giving same images in
the book "Star Testing Telescope Optics", right??
But the source is a laser in contrast to a point source in
telescope objective. But the photons in the laser can also
diverge to make angles right or is it only straight lines as
in laser. If it is, then the image in the detector is a single airy
disc??
This is why I post this in the telescope newsgroup where
people discuss Astrophysics telescopes and Markus triplets
as they are masters of airy discs. So is the Afshar detector
image supposed to be a single airy disc or is it an ensemble
of them just like in a defocused telescope image??
jayz
OG
>
> OG wrote:
>> > You don't seem to get the essence of what Afshar is driving.
>> > Since his detector can detect the photons coming from a
>> > particular pinhole and *at the same wave* a wave charactistic
>> > is detectred (by way of the wires not affected since it's in the
>> > null zone hence implying the wave property). Then particle and
>> > wave is detected at the same time.. which other double slits
>> > experiments were not able to do. This is why it's a Quantum
>> > Bombshell.
>> >
>> > See (for briefing):
>> >
>> > http://en.wikipedia.org/wiki/Afshar_experiment
>> >
>> > http://www.analogsf.com/0409/altview2.shtml
>> >
>> >
>> > jayz
>>
>> I was always a bit sceptical about Ashar's result. It seems to me that
>> although the photon detector purports to detect which pinhole is the
>> source,
>> it does not actually tell us the path of any photon between pinhole and
>> detector.
>
> http://www.sciencefriday.com/images/shows/2004/073004/AfsharExperimentSmall.jpg
>
> The outputs in the detector is a defocused image just like racking
> the focuser in a telescope in and out giving same images in
> the book "Star Testing Telescope Optics", right??
What makes ou think the image at the detector is defocused? Nothing in the
description suggests this is the case
> But the source is a laser in contrast to a point source in
> telescope objective. But the photons in the laser can also
> diverge to make angles right or is it only straight lines as
> in laser. If it is, then the image in the detector is a single airy
> disc??
I don't know; initially you seemed to indicate you understood the point of
Ashfar's experiment. Now it looks like you are only going by what you have
read in the popular press. All I'm saying is that I need some convincing
that Ashfar has overturned complementarity - As I have said, the use of a
lens means we no longer know the photon path, so the 'particle' nature of
the photon is not 'explicit' in the history.
> This is why I post this in the telescope newsgroup where
> people discuss Astrophysics telescopes and Markus triplets
> as they are masters of airy discs. So is the Afshar detector
> image supposed to be a single airy disc or is it an ensemble
> of them just like in a defocused telescope image??
As I see it, it's not really important.
> jayz
>