# What is an Optical Mode .

1. Mar 25, 2013

### Eriance

What is an "Optical Mode".

I've been reading a lot of solar cell articles, especially those having to do with nanophotonics. There is a term that I keep running into, 'optical mode', but I've yet to find an explanation that I can visualize or understand. What exactly is the "mode" being used here? I know it ha to due with confining light to a certain area withing a optical waveguide, but I'm not sure what a mode is. Can someone explain in layman's terms what it is?

2. Mar 26, 2013

### Jano L.

"Mode" refers to "abstract harmonic oscillator describing standing wave". For example, the EM field within metallic cavity can sometimes oscillate in such a way that the electric field at any place oscillates in phase with one common variable $y$ which varies sinusoidally in time.

There are many possible standing wave patterns, and each corresponds to one distinct "mode". This pattern can be complicated, with various nodal surfaces and variation of the maximum amplitude all over the cavity, but the temporal variation is a simple harmonic oscillation with frequency determined by the pattern. The more the number of nodal planes the higher the frequency of the "mode".

3. Mar 26, 2013

### Bill_K

From the book "Nanophotonics",