# Negative Diffraction: Poynting's Vector & Maxwell's Equations

• soikez
In summary, the speaker is seeking information about negative diffraction and asks for help finding articles or papers on the topic. They also inquire about the relationship between wave propagation and energy fluency, as well as the form of Poynting's vector and Maxwell's equations in this case. The expert responds by explaining that the relationship between propagation and fluence is dependent on the amount of lensing present, and suggests considering various sources of lensing. They also mention the possibility of finding information on the topic through research links provided by Dr. Ozbay, who won the Descartes award for their work on negative diffraction.
soikez
Hello, this is the first time I'm sending a message and i don't know so good the procedure. Please forgive me for my english but I'm from greece, thus i am not experienced in speaking english, but i'll try to be as plain as i can.

I'd like to ask something about electromagnetic waves. I'm looking some information about negative diffraction. I've searched the web for any articles or relative papers, but i couldn't find anything.
Have you got any idea where i can search or if you can help me by sending the form of Poynting's vector and the relative between wave propagation and energy fluency on this case?Or the form of Maxwell's equation in this case?

Since negative diffraction is simply a beam of light focusing instead of spreading out (by my simplistic understanding), the relationship between propagation and fluence will depend on the amount of lensing present. There are many sources for this lensing - Thermal lensing, nonlinear self-focusing, the presence of curved surfaces. Meta-materials such as photonic crystals may also exhibit negative diffraction. To obtain an accurate value of the amount of lensing ocuring, you need to take into account all these 'sources'.

I'm confused as to what you mean by the 'form' of Maxwell's equations, as far as I know the form of Maxwell's equations does not vary, just the solutions depending on the boundary conditions.

Claude.

I think there is something about it. Dr. Ozbay won the descartes award because of this. here is a link:
http://www.nanotr.bilkent.edu.tr/
i think you can get some information about negative diffraction in the research link.

Cahit

## 1. What is negative diffraction?

Negative diffraction refers to the phenomenon where the intensity of a wave decreases as it propagates in a certain direction, contrary to what is expected based on traditional diffraction patterns. This occurs when the Poynting vector, which represents the direction and magnitude of energy flow in an electromagnetic wave, points in the opposite direction of the wave's travel.

## 2. How does negative diffraction relate to Poynting's vector?

Negative diffraction is a result of the direction of the Poynting vector being opposite to the direction of wave propagation. This means that the energy flow in the wave is in the opposite direction of its travel, leading to a decrease in intensity.

## 3. What role do Maxwell's equations play in negative diffraction?

Maxwell's equations, which describe the behavior of electromagnetic fields, are used to mathematically model negative diffraction. These equations show that the divergence of the Poynting vector must be negative for negative diffraction to occur.

## 4. Are there any real-world applications for negative diffraction?

Negative diffraction has been observed in experiments involving electromagnetic waves, but its applications are still being explored. One potential application is in creating metamaterials with unique properties, such as negative refraction or focusing of waves in unexpected directions.

## 5. Are there any limitations to negative diffraction?

One limitation of negative diffraction is that it is a relatively new concept and has not yet been fully understood or harnessed for practical applications. Additionally, it is a rare phenomenon and requires specific conditions to occur, making it challenging to replicate consistently.

• Optics
Replies
2
Views
1K
• Electromagnetism
Replies
16
Views
1K
• Other Physics Topics
Replies
3
Views
3K
• Optics
Replies
2
Views
3K
• Optics
Replies
2
Views
5K
• High Energy, Nuclear, Particle Physics
Replies
8
Views
1K
• Electromagnetism
Replies
2
Views
1K
Replies
118
Views
13K
• Chemistry
Replies
9
Views
1K
• Classical Physics
Replies
1
Views
846