SPP at plane interfaces, dispersion curve. confused by textbook?

In summary, the conversation is discussing a dispersion curve plot in a Google book called "Principles of Nano-Optics" by Novotny and Hecht. The plot is on page 388/389 and is describing surface plasmon polaritons. The conversation is specifically focused on an excerpt on page 389 which talks about the dispersion curve bending back and connecting to the upper branch as the frequency increases. The person is confused about what this means and where this "connecting region" can be found on the plot. They also have questions about the physical reason for the increased momentum of the surface plasmon polaritons and the usage of the word "coupling" in this context. They mention using resonance to have a
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the link below should take you to a google book called "principles of nano-optics" by novotny and hecht. my question is on the dispersion curve plot they have on page 388/389 figure 12.5 and 12.6. it is describing the surface plasmon polaritons. the part i don't get is this excerpt which can be found on page 389 about half way down...

"However, as the disperion curve approaches this line the losses start to increase drastically. As a consequence, as [tex] \omega [/tex] is further increased the dispersion curve bends back and connects to the upper branch." (you'll have to look at page 388 fig 12.5 to see both branches they're talkin about)

the bolded part is the part i don't get. what does "bend back" mean? how is it connecting to the upper brancH? the two lines are separated throughout the whole kspace? can someone explain to me what this is and also where the "connecting region" they mention can be found on the plot?

also, at the bottom of pg 389, it says
"the physical reason for the increased momentum of the SPP is the strong coupling between light and surface charges. the light field has to drag the electrons along the metal surface"
i don't get this either. wouldn't dragging the electron cause it to lose speed? and therefore momentum? i know that momentum here is [tex] p = \hbar k[/tex] but it seems that dragging would cause it to lose momentum. and what does the first sentence mean? what is exactly the meaning/usage of the word coupling in this context? how does coupling allow it to have more momentum?http://books.google.com/books?id=Qr...&hl=en&sa=X&oi=book_result&resnum=1&ct=result

thanks guys.
 
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  • #2
I think the [tex]\varpi[/tex] coordinate should be normalized, if you want to have a good comprehension. When [tex]\varpi[/tex] increase, it can not obey the SPPs but the free gas plasmons dispersion in upper band.
 
  • #3
secondly, I do not think dragging is a good term. If you use resonance, you could have a good comprehension. (In my opinion)
 

1. What is SPP at plane interfaces?

SPP stands for Surface Plasmon Polaritons, which are collective oscillations or waves of electrons at the interface between a metal and a dielectric material. They can be excited by light and have unique properties that make them useful in various applications.

2. What is a dispersion curve?

A dispersion curve is a graphical representation that shows the relationship between the momentum and energy of a wave. In the context of SPP at plane interfaces, it shows the relationship between the momentum and the frequency of the surface plasmon polariton.

3. How is the dispersion curve of SPP at plane interfaces different from other types of dispersion curves?

The dispersion curve of SPP at plane interfaces is unique because it exhibits a negative slope, which means that as the momentum increases, the frequency decreases. This is in contrast to most other dispersion curves, which have a positive slope.

4. Why am I confused by the textbook's explanation of SPP at plane interfaces?

The concept of SPP at plane interfaces can be complex and difficult to understand, especially for those who are not familiar with the principles of plasmonics. The textbook may use technical language and equations that can be overwhelming for beginners. It is important to seek additional resources and clarification from a teacher or tutor if needed.

5. What are some real-world applications of SPP at plane interfaces?

SPP at plane interfaces have various applications in fields such as biosensing, solar cells, and nanophotonics. They can be used to enhance light-matter interactions and improve the sensitivity of biosensors. In solar cells, SPPs can increase the absorption of light, leading to higher efficiency. In nanophotonics, they can be used for subwavelength imaging and data transmission.

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