How Do Photons and Detectors Shape Our Perception of Images?

[waves and change]

General question regarding how images are formed. As you move your eye "detector" around a illuminated room. The is image of let's say "a book" is in every position in the room at a given time correct--even before you "look" at it? The photons reflected off the book have formed an image of the book in every location in the room but it is not until a detector" the eye" is at a specific location to gather the information packed in the photon wave function that the image is generated. Is this a correct way of looking at this scenario?

 

[kuruman]

The is image of let's say "a book" is in every position in the room at a given time correct--even before you "look" at it?

It is the lens of the eye that forms an image on the retina which is interpreted by the brain as an object. The image does not otherwise exist. If you place just a piece of photographic film in a room, you will not get an image of the objects in the room on the film without using a camera that has a lens.

 

[waves and change]

Understood with regards to the photographic film but nonetheless the the information of the image is everywhere in the room. Their are photons at every point in the room which have the information of the image, if that makes sense.

 

[waves and change]

Place an “eye” anywhere in the room and information of every object in the room is “ stored in that point in space via a photons.

 

[davenn]

Understood with regards to the photographic film but nonetheless the information of the image is everywhere in the room. Their are photons at every point in the room which have the information of the image, if that makes sense.

no it isn't

no it doesn't

There

There are EM waves bouncing all around the room ... it's ONLY the EM waves, and I hate to use the word photons, that come directly from an object to your eye or directly to a camera that are detected and resolved into that object

Place an “eye” anywhere in the room and information of every object in the room is “ stored in that point in space via a photons.

nothing (EM or photons) is stored anywhere in the room

reread @kuruman 's post

 

[waves and change]

That is semantics with regards to “stored” and incorrect as well a photon or EM in a room obviously store energy. The fields have an associated energy. Don’t know what “ nothing is stored anywhere” even means ? Can you clarify

 

[waves and change]

no it isn't

no it doesn't

There

There are EM waves bouncing all around the room ... it's ONLY the EM waves, and I hate to use the word photons, that come directly from an object to your eye or directly to a camera that are detected and resolved into that object
nothing (EM or photons) is stored anywhere in the room

reread @kuruman 's post

That is semantics with regards to “stored” and incorrect as well a photon or EM in a room obviously store energy. The fields have an associated energy. Don’t know what “ nothing is stored anywhere” even means ? Can you clarify

 

[davenn]

That is semantics with regards to “stored”

no it isn't ... the word stored has a very specific meaning, with is totally irrelevant in the current discussion

Don’t know what “ nothing is stored anywhere” even means ? Can you clarify

read the above comment ... it is irrelevant ... no EM is stored in the room

 

[Nugatory]

General question regarding how images are formed. As you move your eye "detector" around a illuminated room. The is image of let's say "a book" is in every position in the room at a given time correct--even before you "look" at it?

An image forms when you use a lens to focus the light onto a surface (retina of your eye, photographic film, ...) in such a way that the intensity at each point on the surface is correlated with intensity of the light reflected off the corresponding point on the book. So your description above isn't quite right; the one below (with the corrections I've made) where you say that the information is there but you need a device to gather it up and form the image is better.

The photons electromagnetic waves reflected off the book have formed an image of the book in every location in the room but it is not until a detector" the eye" is at a specific location to gather the information packed in the photon wave function time-varying electromagnetic fields at location that the image is generated.

Photons (which don't even have a wave function) don't come into this process at all - the whole thing is straightforward classical electrodynamics working with classical electromagnetic radiation and classical optics.

 

[waves and change]

An image forms when you use a lens to focus the light onto a surface (retina of your eye, photographic film, ...) in such a way that the intensity at each point on the surface is correlated with intensity of the light reflected off the corresponding point on the book. So your description above isn't quite right; the one below (with the corrections I've made) where you say that the information is there but you need a device to gather it up and form the image is better.Photons (which don't even have a wave function) don't come into this process at all - the whole thing is straightforward classical electrodynamics working with classical electromagnetic radiation and classical optics.

Thank you for insight. And my mistake saying photons wave function which is incorrect. The main point I wanted clarification on is whether the “information” which has the potential to form an image exists in a given point in the room.

 

[jbriggs444]

Thank you for insight. And my mistake saying photons wave function which is incorrect. The main point I wanted clarification on is whether the “information” which has the potential to form an image exists in a given point in the room.

At a "point" of zero size: no. There is zero energy passing through a single point and zero information available.

In an arbitrarily small region around any point you pick, yes. Stick a lens there. The smaller the region (i.e. the smaller the aperture) the longer you have to wait (i.e. the longer the exposure) before an image can become detectable. [And for smaller apertures, diffraction makes image decoding more challenging]

 

[lekh2003]

Imagine you are blind. When a little ball hits you and you figure out that a ball is coming from somewhere and that it has just hit you, you became aware of an object or source where that ball came from. In some sense, a physical possible location and image of the source of that ball has just been made. When you are not in the room and the ball is bouncing around wildly not hitting into you, it has no stored information because there is nothing there to interpret something from its movement.

Photons are the same. They are actually just arbitrary EM waves which humans have evolved to detect. Their bouncing about is interpreted by the retina into an image. Otherwise, they are just balls bouncing about with no actual purpose.

 

[Vanadium 50]

Photons are the same.

Photons are not little balls. See Nugatory's message.

 

[sophiecentaur]

Their are photons at every point in the room which have the information of the image, if that makes sense.

Your picture of Photons is very misguided. As has been pointed out many times on PF, they are nothing like the little bullets that people imagine. There is no particular "point" at which a photon exists until it actually interacts with an object. You have made the common mistake of assuming that introducing the photon idea is of any earthly use in discussing optics or that it enhances understanding. All of Optics is far better dealt with, using waves. Waves are not a 'second best' description. They are the way to do it. If you want to claim otherwise then you would, at least, have to give a credible reference and demonstrate how your little bullet model gives the right result.
This whole question is far better explained by introducing the phenomenon of Diffraction which describes how waves are modified as they pass through or by obstructions. An 'Image' is formed when waves, emanating in different directions from an object, come together in phase and arrive together in a pattern that maps the pattern of the object. The formation of a 'good' image requires an aperture of some finite width and also some mechanism (e.g. a suitable lens or converging mirror) to bring the waves together coherently.
Light Waves are emanating from every point in every direction. All those waves carry information about the brightnesses and positions of parts of the room (etc). If you took a lens, say, to any point in your room, it would accept waves from all directions, including your point of interest on the wall, and produce a detailed image in one particular place on a screen (when "focussed" for optimum effect). A lens placed elsewhere could also produce an image by gathering and 'assembling' the waves hitting it.
You could usefully re-state "Their are photons at every point in the room which have the information of the image," as "Their are waves traveling past every point in the room which have the information of the image."

 

[lekh2003]

Photons are not little balls. See Nugatory's message.

I meant that photons can be thought of like this in this situation. Sorry if it was misleading.

 

[sophiecentaur]

I meant that photons can be thought of like this in this situation. Sorry if it was misleading.

They can't, if they aren't in fact what you imply.
Why not do this 'properly' (i.e. in a way that actually works)?

 

[Vanadium 50]

Reinforcing an incorrect picture is not helpful.

 

[waves and change]

Photons are not little balls. See Nugatory's message.

Photons can be though of as “ little balls” in the sense that they act as particles when they interact with matter... ie the photoelectric effect. The formalism that best describes the way light travels is to regard it as a wave but to consider it as a particle when it interacts with matter Ie ...a photomultiplier

 

[waves and change]

Your picture of Photons is very misguided. As has been pointed out many times on PF, they are nothing like the little bullets that people imagine. There is no particular "point" at which a photon exists until it actually interacts with an object. You have made the common mistake of assuming that introducing the photon idea is of any earthly use in discussing optics or that it enhances understanding. All of Optics is far better dealt with, using waves. Waves are not a 'second best' description. They are the way to do it. If you want to claim otherwise then you would, at least, have to give a credible reference and demonstrate how your little bullet model gives the right result.
This whole question is far better explained by introducing the phenomenon of Diffraction which describes how waves are modified as they pass through or by obstructions. An 'Image' is formed when waves, emanating in different directions from an object, come together in phase and arrive together in a pattern that maps the pattern of the object. The formation of a 'good' image requires an aperture of some finite width and also some mechanism (e.g. a suitable lens or converging mirror) to bring the waves together coherently.
Light Waves are emanating from every point in every direction. All those waves carry information about the brightnesses and positions of parts of the room (etc). If you took a lens, say, to any point in your room, it would accept waves from all directions, including your point of interest on the wall, and produce a detailed image in one particular place on a screen (when "focussed" for optimum effect). A lens placed elsewhere could also produce an image by gathering and 'assembling' the waves hitting it.
You could usefully re-state "Their are photons at every point in the room which have the information of the image," as "Their are waves traveling past every point in the room which have the information of the image."

Your claim that photons are nothing like the bullets people imagine is not correct. A photon interacts with matter like a particle. If your claim was true how would you explain the photoelectric effect which treats a photon as a “bullet”.

 

[ZapperZ]

Photons can be though of as “ little balls” in the sense that they act as particles when they interact with matter... ie the photoelectric effect. The formalism that best describes the way light travels is to regard it as a wave but to consider it as a particle when it interacts with matter Ie ...a photomultiplier

Actually, it can't. "Little balls" have a lot of physical connotations that are not supported by physics when applied to photons. The ONLY similarities here is that each photon carries a specific amount of energy. But this doesn't imply that that they are like "little balls". You might as well say that an egg is like a cow, simply based on the characteristic that they are both edible.

The photoelectric effect, while it is a strong evidence for the photon picture, does NOT completely disprove the wave scenario (do a search on here, it has been discussed numerous times in numerous threads). The which-way experiments and the anti-bunching properties are more definitive.

BTW, a "photomultiplier" is nothing more than the photoelectric effect, with the initial photoelectrons being multiplied by an additional structure. It is not a property of an interaction with matter.

Zz.

 

[sophiecentaur]

Your claim that photons are nothing like the bullets people imagine is not correct. A photon interacts with matter like a particle. If your claim was true how would you explain the photoelectric effect which treats a photon as a “bullet”.

Quantisation and bullets are not related in any obvious way. If a photon is like a bullet, how can it be involved in diffraction? Of course there no question about the quantised behaviour of EM but it's risk and nonsense to go the whole way or we're back in the Corpuscular Theory. Bullets have mass; do photons?
If you want to explain a wave phenomenon the use waves.

 

[waves and change]

Actually, it can't. "Little balls" have a lot of physical connotations that are not supported by physics when applied to photons. The ONLY similarities here is that each photon carries a specific amount of energy. But this doesn't imply that that they are like "little balls". You might as well say that an egg is like a cow, simply based on the characteristic that they are both edible.

The photoelectric effect, while it is a strong evidence for the photon picture, does NOT completely disprove the wave scenario (do a search on here, it has been discussed numerous times in numerous threads). The which-way experiments and the anti-bunching properties are more definitive.

BTW, a "photomultiplier" is nothing more than the photoelectric effect, with the initial photoelectrons being multiplied by an additional structure. It is not a property of an interaction with matter.

Zz.

Your answering your own questions. I never disregarded the duality with regards to photons behaving as waves when propagating. I simply said they act particle like when they interact with matter such as knocking electrons off a material- a photomultiplier was just an example.

 

[waves and change]

Quantisation and bullets are not related in any obvious way. If a photon is like a bullet, how can it be involved in diffraction? Of course there no question about the quantised behaviour of EM but it's risk and nonsense to go the whole way or we're back in the Corpuscular Theory. Bullets have mass; do photons?
If you want to explain a wave phenomenon the use waves.

I was simply attempting to get the point across that photons interact with materials such as solar cells in a particle like way. Yes, a bullet is not a good example because as you said it propagates in a way best formalized using wave like behavior.

 

[ZapperZ]

Your answering your own questions. I never disregarded the duality with regards to photons behaving as waves when propagating. I simply said they act particle like when they interact with matter such as knocking electrons off a material- a photomultiplier was just an example.

First of all, how was I "answering my own questions" when I didn't ask any?

You need to look at the non-photon description of the photoelectric effect. There is no "act particle like" in this case. (read 1st paragraph of this paper, and references therein: http://people.whitman.edu/~beckmk/QM/grangier/Thorn_ajp.pdf)

The photomultiplier example you gave was wrong, because you said that ".. consider it as a particle when it interacts with matter Ie ...a photomultiplier... " This is incorrect, because the example of a photomultiplier is NOT how photons interact with matter, i.e. there is often no "multiplication"! If you simply have stuck with your photoelectric effect, I wouldn't have touched it.

Zz.

 

[waves and change]

First of all, how was I "answering my own questions" when I didn't ask any?

You need to look at the non-photon description of the photoelectric effect. There is no "act particle like" in this case. (read 1st paragraph of this paper, and references therein: http://people.whitman.edu/~beckmk/QM/grangier/Thorn_ajp.pdf)

The photomultiplier example you gave was wrong, because you said that ".. consider it as a particle when it interacts with matter Ie ...a photomultiplier... " This is incorrect, because the example of a photomultiplier is NOT how photons interact with matter, i.e. there is often no "multiplication"! If you simply have stuck with your photoelectric effect, I wouldn't have touched it.

Zz.

Thanks for the reference. I understand the quantum nature of the interaction makes a particle like description less coherent. That being said; would you say that single electrons being knocked off a material if the photons energy exceeds the work function to be particle like?

 

[ZapperZ]

Thanks for the reference. I understand the quantum nature of the interaction makes a particle like description less coherent. That being said; would you say that single electrons being knocked off a material if the photons energy exceeds the work function to be particle like?

No, because if it is THAT obvious, the "particle" picture would have already been used before Einstein's photoelectric effect model. There are other experiments that are more convincing.

I'm not sure why you'd even ask me that question IF you have read the first paragraph of that paper and checked out the corresponding reference.

Zz.

 

[waves and change]

No, because if it is THAT obvious, the "particle" picture would have already been used before Einstein's photoelectric effect model. There are other experiments that are more convincing.

I'm not sure why you'd even ask me that question IF you have read the first paragraph of that paper and checked out the corresponding reference.

Zz.

Is this the current consensus that the particle-wave duality does not exist in this context?

 

[sophiecentaur]

I never disregarded the duality with regards to photons behaving as waves when propagating.

"Duality" is a term that was discarded many years ago.
You are still trying to sneak the Photon as the primary entity for EM. Particles don't behave as waves, particles behave as particles and waves behave as waves. The object that interacts with EM energy is affected as if it has launched or received a particle. The process of propagation between the ends of the journey is best described by the wave model. You have to avoid the question "what is it really?" because anything in Science is only describable by the way it behaves at the time.
You need to discard what the popular Science press and School teachers tell you if you want to understand the current models. Intuitive models will always let you down in the end.

would you say that single electrons being knocked off a material if the photons energy exceeds the work function to be particle like?

I would say that (with tongue in cheek, perhaps).

 

[waves and change]

"Duality" is a term that was discarded many years ago.
You are still trying to sneak the Photon as the primary entity for EM. Particles don't behave as waves, particles behave as particles and waves behave as waves. The object that interacts with EM energy is affected as if it has launched or received a particle. The process of propagation between the ends of the journey is best described by the wave model. You have to avoid the question "what is it really?" because anything in Science is only describable by the way it behaves at the time.
You need to discard what the popular Science press and School teachers tell you if you want to understand the current models. Intuitive models will always let you down in the end.

I would say that (with tongue in cheek, perhaps).

I don’t see what the disagreement is here. I’ve stated numerous times that EM waves are used to describe the propagation of light and that the interaction between a material and EM waves has a particle like aspect like you just stated. Where am I Sneaking in a photon to be primary?

 

[Nugatory]

Photons can be though of as “ little balls” in the sense that they act as particles when they interact with matter... ie the photoelectric effect. The formalism that best describes the way light travels is to regard it as a wave but to consider it as a particle when it interacts with matter Ie ...a photomultiplier

That's not a very good of thinking about it either. You're moving in the right direction when you focus on the interaction with matter, but even in these interactions they don't act like little balls. We could reasonably say that interactions between matter and the electromagnetic field always exchange energy and momentum in discrete amounts, but that leads to a picture that is very un-ball-like.

 

[waves and change]

That's not a very good of thinking about it either. You're moving in the right direction when you focus on the interaction with matter, but even in these interactions they don't act like little balls. We could reasonably say that interactions between matter and the electromagnetic field always exchange energy and momentum in discrete amounts, but that leads to a picture that is very un-ball-like.

Agreed, the interaction is not wave like because the “discreteness” but not ball-like either

 

[sophiecentaur]

Where am I Sneaking in a photon to be primary?

When you say "with regards to photons behaving as waves when propagating".
If you would also say "with regards to waves behaving as photons during interaction" then that would be equally biased the other way.

 

[waves and change]

"Duality" is a term that was discarded many years ago.
You are still trying to sneak the Photon as the primary entity for EM. Particles don't behave as waves, particles behave as particles and waves behave as waves. The object that interacts with EM energy is affected as if it has launched or received a particle. The process of propagation between the ends of the journey is best described by the wave model. You have to avoid the question "what is it really?" because anything in Science is only describable by the way it behaves at the time.
You need to discard what the popular Science press and School teachers tell you if you want to understand the current models. Intuitive models will always let you down in the end.

I would say that (with tongue in cheek, perhaps).

I suggest you look into this regarding your statement that particles behave as particles and waves behave as waves which is incorrect in many contexts.

https://www.photonics.com/a52250/Photons_Observed_as_Particles_Waves

 

[waves and change]

When you say "with regards to photons behaving as waves when propagating".
If you would also say "with regards to waves behaving as photons during interaction" then that would be equally biased the other way.

Duality being discarded? Please site references explaining that? That is an incorrect statement

 

[sophiecentaur]

I suggest you look into this regarding your statement that particles behave as particles and waves behave as waves which is incorrect in many contexts.

https://www.photonics.com/a52250/Photons_Observed_as_Particles_Waves

Did you notice the title? Photons observed as Particles and Waves. Of course photons can be 'observed' one way or another and, under special conditions (as in the experiments described) both behaviours can be observed. I saw that the word Duality appears three times in that reference; once in a quote from Feynman (not recent) and twice in the words of the journalist, reporting on the experiment. Have you ever had your words quoted by a journalist? It is not always a reliable process.
But does this really have anything at all to do with the situation of the scale that is described in the OP? The answer to that question is available with simple ray optics. The general opinion of PF is that photons do not help with that question.

 

[waves and change]

Did you notice the title? Photons observed as Particles and Waves. Of course photons can be 'observed' one way or another and, under special conditions (as in the experiments described) both behaviours can be observed. I saw that the word Duality appears three times in that reference; once in a quote from Feynman (not recent) and twice in the words of the journalist, reporting on the experiment. Have you ever had your words quoted by a journalist? It is not always a reliable process.
But does this really have anything at all to do with the situation of the scale that is described in the OP? The answer to that question is available with simple ray optics. The general opinion of PF is that photons do not help with that question.

Your statement verbatim that duality has been discarded is in complete contradiction to what you just said. You just stated that photons can be observed to be particle like and wave like. That is what duality is. This experiment shows a possible superposition of those properties. This is not the only recent observation of similar phenomena

 

[weirdoguy]

Duality being discarded? Please site references explaining that?

It has been discussed here multiple times... E.g. read this:
https://www.physicsforums.com/threads/why-does-wave-particle-duality-not-exist-anymore.910647/

Ever since quantum mechanics was developed, wave-particle duality is treated only as a heuristic, not any part of a mathematical formalism of quantum mechanics, nor quantum field theory. Reference? Most of textbooks on QM or QFT.

 

[Nugatory]

I suggest you look into this regarding your statement that particles behave as particles and waves behave as waves which is incorrect in many contexts.
https://www.photonics.com/a52250/Photons_Observed_as_Particles_Waves

That is a non-technical PR summary intended for laypeople, so is not an acceptable reference under the physics forums rules (and the phrase "Artist’s impression, inspired by the work of the artist Maurits Cornelis Escher" is something of a warning here). The actual published paper (available free after a mildly annoying registration process) is much more serious but doesn't do much to support any of the informally stated English-language positions being argued in the last few posts.

In any case, we are far off the topic of the original post and thread title, so we can close the thread. Further questions on the nature of photons and the status of wave-particle duality in modern (after 1925) quantum physics should be started in new threads - but please please take a look at some of the many threads on these topics that we already have.