[alancalverd]

Quote from: alancalverd on Today at 09:09:55
According to Hamamatsu (who know a thing or two about their products) photocathode emission is strongly wavelength-dependent
The glass window material contributes significantly to that dependency.

The graph I copied is for reflection photocathodes, not for complete photomultipliers or transmission cathodes, where the glass contributes to the overall response.

[alancalverd]

Quote from: alancalverd on Yesterday at 23:53:56
The best optical photocathodes have a quantum efficiency of around 30%
And also more than 1
Quote from: alancalverd on Yesterday at 14:55:43
determines how many electrons are emitted from the first interaction.
It's never "electrons" i,.e. plural, is it?

Suddenly I can't think of an alternative idiomatic phrase that meets the criteria of succinctness and precision. Unless you are prepared to believe that electrons are divisible. "How much of an electron" will only add to HY's confusion!

[Bored chemist]

Quote from: alancalverd on Yesterday at 23:53:56
The best optical photocathodes have a quantum efficiency of around 30%
And also more than 1
Quote from: alancalverd on Yesterday at 14:55:43
determines how many electrons are emitted from the first interaction.
It's never "electrons" i,.e. plural, is it?

Suddenly I can't think of an alternative idiomatic phrase that meets the criteria of succinctness and precision. Unless you are prepared to believe that electrons are divisible. "How much of an electron" will only add to HY's confusion!

It's not rocket science.
The wavelength (among other things) determines the probability of the electron being ejected.
It's about a 1 in 3 chance, but you don't get a third of an electron, (nor do you get 3 electrons).

[hamdani yusuf (OP)]

A is events of a photon hitting detector.
B is detector showing an activity.

We can assume that there are detected photons, depicted by A ∩ B.
We know that the efficiency is less than 100%, so there are undetected photons, depicted by A ∩ ~B.
We also know that temperature can increase detection rate, even when the light source is off. The detections without photon are depicted by ~A ∩ B.
You can define that A=B, but consequently, you must ignore two last cases above.

The electron ejection you described reminds me of Newton's cradle.

[alancalverd]

temperature can increase detection rate, even when the light source is off.

If the light is off there can be no "detection rate" because there is nothing to detect.

The problem of "dark current" is usually resolved by placing a chopper blade in the light beam and using a synchronous detector to subtract the dark current (and other noise) from the signal + noise.

Compensating for the temperature dependence of photon yield is a bit more difficult in many real life applications but you can use a reference beam, temperature stabilisation, or temperature measurement and correction, to get a more consistent measurement. 

[Bored chemist]

You can define that A=B,

No, we don't.
If it was then the yield would be exactly 1 and it isn't.

Why did you represent what we say

The electron ejection you described reminds me of Newton's cradle.

They both work.

[wolfekeeper]

Maybe this should be moved to New Theories, it no longer seems to be standard physics. Can classical waves replace the theory of quantum mechanical photons? No. Next question.

[hamdani yusuf (OP)]

Maybe this should be moved to New Theories, it no longer seems to be standard physics. Can classical waves replace the theory of quantum mechanical photons? No. Next question.

I agree. If what you mean with classical wave is the one based on Maxwell's equations, it certainly can't explain what we observed. He didn't even know about electron.
I think I'll just create a new thread in new theory section to discuss about this further.

[alancalverd]

I don't see any new theory here. We are discussing well-known phenomena that are adequately described by two different mathematical models. The only problem seems to be the recurring misunderstanding that "described by" (physics) doesn't mean "is" (philosophy).

So to answer the question, yes, a simple particle model is an oversimplification, as is a continuous wave model, but we use both to predict (with considerable accuracy) how electromagnetic radiation is generated and what happens when it interacts with stuff.

[hamdani yusuf (OP)]

I don't see any new theory here. We are discussing well-known phenomena that are adequately described by two different mathematical models. The only problem seems to be the recurring misunderstanding that "described by" (physics) doesn't mean "is" (philosophy).

You're right. I haven't put any new theory here. I simply pointed out some problems I have with commonly used theory in explaining the behavior of light.

[hamdani yusuf (OP)]

Phonons are quantum mechanical phenomena, just like photons in fact.

Photons and how they interact with electrons are extremely well described in modern physics by quantum electrodynamics:

https://en.wikipedia.org/wiki/Quantum_electrodynamics

Do quantum electrodynamics correctly describe how photons interact with macroscopic objects, such as knife edge, single slit and double slit experiment, also their equivalents according to Babinet's principle, i.e. single wire and double wire experiment?
Does it predict the existence of non-diffractive edge and non-diffractive slit?

[alancalverd]

I'm not even sure you have described any "problems with the theory". We have two mathematical models that describe what actually happens at the macroscopic level, and QED gives us a good insight into photon-electron interactions, leading to probability amplitudes for scattering etc. that do not conflict with observaton.

[hamdani yusuf (OP)]

I'm not even sure you have described any "problems with the theory". We have two mathematical models that describe what actually happens at the macroscopic level, and QED gives us a good insight into photon-electron interactions, leading to probability amplitudes for scattering etc. that do not conflict with observaton.

Does the theory describes the criteria, when to use one model, when to use the other?

Do quantum electrodynamics correctly describe how photons interact with macroscopic objects, such as knife edge, single slit and double slit experiment, also their equivalents according to Babinet's principle, i.e. single wire and double wire experiment?
Does it predict the existence of non-diffractive edge and non-diffractive slit?

How does it describe polarization?

If you consider polarisation as a classical electromagnetic phenomenon, there is no "paradox".

What makes me wonder is why it was called paradox in the first place if it is clearly explained by classical physics? Have previous generation physicists overlooked it?

Albert Einstein said of Dirac and polarization,
"Dirac, to whom, in my opinion, we owe the most perfect exposition, logically, of this [quantum] theory, rightly points out that it would probably be difficult, for example, to give a theoretical description of a photon such as would give enough information to enable one to decide whether it will pass a polarizer placed (obliquely) in its way or not." Maxwell's Influence on the Evolution of the Idea of Physical Reality...1931, Ideas and Opinions, p.270

Here is my experiment showing that polarizer does rotate the microwave. You can skip to 3:30.

[alancalverd]

As I see it, QED will give you a good idea of the probability of a photon being emitted from an electron process in a single atom. SInce the electron can be anywhere and move to anywhere else as the photon is emitted, there is no preferred or predictable direction or polarisation of a single photon. Polarised light, i.e. light consisting of several photons sharing a preferred polarisation, requires the intervention of some kind of lattice or surface that defines a direction and radiates or re-radiates preferentially - it is necessarily a mesoscopic, collaborative process that must be modelled by wave analysis.

[Bored chemist]

it is necessarily a mesoscopic, collaborative process that must be modelled by wave analysis.

Define mesoscopic in this context.

https://en.wikipedia.org/wiki/Synchrotron_radiation#Polarization_of_synchrotron_radiation


But the important thing is we have mathematical models which work just fine; including for this rather weird case.
So it's not clear what problem the OP is trying to solve.

[alancalverd]

Synchrotron radiation is produced when moving particles accelerate, e.g. when electrons move freely in a magnetic field.

We aren't dealing with single photon-electron QED interactions but the classical stuff of Maxwell, with the electron movement constrained by the magnetic field.  The analysis is similar to a radiofrequency dipole where the alternating current is constrained by a conductor, so that the radiated wave is polarised by the (mesoscopic!) shape of the conductor..

[hamdani yusuf (OP)]

If we think that currently existing theory is already perfect, then there's nothing we can do to improve it. Any changes/modifications will only make it worse.

On the other hand, if we think that currently existing theory is not perfect, then there's something we can do to improve it. But first we need to identify its weaknesses/flaws/limitations. We can compare between what the theory predicts and what the observed results are. Are they always identical? If some differences are found, can we identify the causes of those differences?

[hamdani yusuf (OP)]

But the important thing is we have mathematical models which work just fine; including for this rather weird case.
So it's not clear what problem the OP is trying to solve.

Can you demonstrate using your mathematical models that single slit experiment would produce similar pattern as single wire experiment?
Can you demonstrate using your mathematical models that double slit experiment would produce similar pattern as double wire experiment?
Can you demonstrate using your mathematical models that shining a laser pointer to a vertically tilted diffraction grating would produce a cone shaped beam?

Does it predict the existence of non-diffractive edge and non-diffractive slit?

What do your mathematical models predict with this proposed experiment?

I have an idea to test the validity of the wave explanation. Let's make the long path of the interfering light beam much longer than the short path, so there's a significant time difference in their arrival at the screen. To balance the intensity, the short path can be reduced further using a filter.

First, the light source is turned on continuously. The single photon production is done using attenuating filter alone. As demonstrated in the video, the screen shows interference pattern.

Second the light source is turned on in short pulses. The pulse width is shorter than time difference between the paths of the light beams. The silence period between the pulses should be randomized to minimize the effect from resonance or echo. If the wave explanation is correct, then the interference pattern should not be observed significantly.

The half mirrors can be made to reflect more than 50% to compensate longer distance and loss in bottom mirrors.

[alancalverd]

I have an idea to test the validity of the wave explanation.

It's not an explanation! It's a mathematical model of some of the properties of electromagnetic radiation. It (very accurately) predicts the outcome of an experiment.

I can devise an experiment to weigh an elephant, based on the mathematics of levers or hydraulics. It doesn't tell me what an elephant is, or how fast it can run, but it's a damn good model of the effects of gravity on a mammal!

[hamdani yusuf (OP)]

I have an idea to test the validity of the wave explanation.

It's not an explanation! It's a mathematical model of some of the properties of electromagnetic radiation. It (very accurately) predicts the outcome of an experiment.

What's the outcome predicted by your mathematical model in following experiments?
- Single slit
- double slit
- single wire
- double wire
- vertically tilted diffraction grating?
- non-diffractive edge?
- non-diffractive slit?

I can devise an experiment to weigh an elephant, based on the mathematics of levers or hydraulics. It doesn't tell me what an elephant is, or how fast it can run, but it's a damn good model of the effects of gravity on a mammal!

The experiment I proposed was to verify/refute the explanation in the video using wave model.

I just found a video explaining this topic pretty convincingly. The best part IMO, is that he made the experiment in real life, not just a simulation.

The result from weighing the elephant can be used to predict if a particular helicopter can be used to lift it.