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

[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?

Thank you for your patience.

 

[Claude Bile]

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.

 

[alicahit]

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