[Zer0]

Finally this OP seems to be getting somewhere...Good!

P.S. - 👍

[Bored chemist]

I've shown non-diffractive edge in experiments using total internal reflection in visible light.

Can you post a link?

video #4 Non-diffractive Obstacle

I said that deflection of light beam to the left, i.e. the area behind the obstacle, can't be explained by reflection, as well as refraction. It's a separate phenomenon called diffraction.

What the hell point were you trying to make with the video then?

[alancalverd]

I said that deflection of light beam to the left, i.e. the area behind the obstacle, can't be explained by reflection, as well as refraction. It's a separate phenomenon called diffraction.

So far, classical physics. And a well-known problem solved daily in classrooms around the world, at all wavelengths from  "Elementary Radio Navigation" to "Introduction to X-ray Crystallography".

[hamdani yusuf (OP)]

I've shown non-diffractive edge in experiments using total internal reflection in visible light.

Can you post a link?

video #4 Non-diffractive Obstacle

I said that deflection of light beam to the left, i.e. the area behind the obstacle, can't be explained by reflection, as well as refraction. It's a separate phenomenon called diffraction.

What the hell point were you trying to make with the video then?

The fact that a self-declared scientist like you don't get the point makes my point exactly.
26 seconds into the first video shows the diffraction produced in the edge of a normal/ordinary obstacle.
My explanation on non-diffractive edge can be found at 3:24 time stamp. Thus, you've skipped 3 minutes before writing a comment, which made you miss my point.

[hamdani yusuf (OP)]

It is indeed accurately modelled by wave diffraction, but with my pedant hat on I can't agree that it is explained, since what we actually observe at any point downstream is a quantum phenomenon!

Declaring that a phenomenon is quantum doesn't give a legitimate reason to discard the efforts to search for a simpler or more consistent explanation.

The video below starting at 13:00 and 14:00 shows that the light propagates in observable trajectory. No need to introduce quantum mysticism here.

Here's another video from a science Youtuber, experimenting on diffraction and interference of light.

[hamdani yusuf (OP)]

26 seconds into the first video you say that diffraction by a single edge can not be explained.

In fact, it can be explained (and modeled).
https://physics.stackexchange.com/questions/232254/how-to-calculate-a-straight-edge-diffraction-pattern

Here's a diagram shown in the link above.

This pattern can only appear with diverging light beam before hitting a diffractive edge. My experiment in
video #11 Non-parallel light source
shows this phenomenon.
Single edge diffraction of a narrow parallel light beam like an ordinary laser pointer doesn't produce interference pattern.

[hamdani yusuf (OP)]

I've recorded some raw footages for new videos investigating diffraction of light. One of them explores more on horizontally tilted diffraction. There's also demonstration of half interference pattern from same sided diffraction edges. There are also a few more.
I'll upload them once I finished the editing.

[hamdani yusuf (OP)]

It is indeed accurately modelled by wave diffraction, but with my pedant hat on I can't agree that it is explained, since what we actually observe at any point downstream is a quantum phenomenon!

How does treating it as quantum phenomenon improve the accuracy of prediction in single edge diffraction?

[alancalverd]

It doesn't.

Diffraction can only be modelled by wave equations, detection (at optical and shorter wavelengths) by quantum mechanics.

[hamdani yusuf (OP)]

From my experience, diffraction requires partial opacity/transparency. Perfectly opaque objects, as well as perfectly transparent objects don't produce observable diffraction.

I haven't found a published source mentioning the necessity of partial opacity/transparency of the obstacle to produce diffraction of light. Please let me know if I miss something.

[hamdani yusuf (OP)]

It doesn't.

Diffraction can only be modelled by wave equations, detection (at optical and shorter wavelengths) by quantum mechanics.

Even at optical and shorter wavelengths, wave model can still make a good prediction. Quantization only becomes apparent at low amplitude, which then requires ultrasensitive sensors to detect. The possibility that the quantization is a feature of the sensor itself instead of the characteristics of the incoming light hasn't been adequately eliminated.

[alancalverd]

It was the failure of the wave model to predict the photoelectric effect that led to the establishment of quantum theory.

The granularity of sand is only apparent close up and in small quantities, but it would be foolish to assume it to be a feature of your hand, because it is the same for all sensors.

However we measure the energy of a monchromatic source, we get the same answer. Better still, there is a very simple school experiment where you apply an increasing voltage to a set of LEDs. To nobody's surprise, they light up in the order red, yellow, green, at exactly the forward voltage corresponding to the photon energy  you can measure with a photocell.

[hamdani yusuf (OP)]

It was the failure of the wave model to predict the photoelectric effect that led to the establishment of quantum theory.

That's true, for wave models based on analogy of mechanical waves like sound and wave on water surface. Other kinds of wave can be built to conform to photoelectric effect.
Schrodinger equation to describe atoms is also a wave model.

[hamdani yusuf (OP)]

The granularity of sand is only apparent close up and in small quantities, but it would be foolish to assume it to be a feature of your hand, because it is the same for all sensors.

Your analogy fails because grains of sand can be observed independently using other methods. I haven't found any sensor whose working principle is based on the movement of particles smaller than electrons.

[hamdani yusuf (OP)]

However we measure the energy of a monchromatic source, we get the same answer.

A strictly monochromatic photon in a finite amount of time is a mathematical impossibility, as I've shown in reply#14 on the first page of this thread.

[hamdani yusuf (OP)]

Better still, there is a very simple school experiment where you apply an increasing voltage to a set of LEDs. To nobody's surprise, they light up in the order red, yellow, green, at exactly the forward voltage corresponding to the photon energy  you can measure with a photocell.

How do you relate it to quantization of light?
How does a photon produced in an atom?

[Bored chemist]

Single edge diffraction of a narrow parallel light beam

What made the beam narrow?

[Bored chemist]

The fact that a self-declared scientist like you don't get the point makes my point exactly.
26 seconds into the first video shows the diffraction produced in the edge of a normal/ordinary obstacle.
My explanation on non-diffractive edge can be found at 3:24 time stamp. Thus, you've skipped 3 minutes before writing a comment, which made you miss my point.

I asked for a link, not a library.
The first thing I came across in your gish gallop flatly contradicted what you said you were trying to demonstrate.
Why did you think I would plough on through the rest of it?

[Bored chemist]

Could someone please give me a transcript of the first 30 seconds or so of this video. I don't think it's very clear.

Thanks
I don't want to influence you by saying what I think it says.

[hamdani yusuf (OP)]

Single edge diffraction of a narrow parallel light beam

What made the beam narrow?

Collimating lens.