Understanding Normal Modes of Light Propagation in Anisotropic Crystals

[taimoortalpur]

Dear Friends,
I am new to this forum and I am not sure whether I am writing my Query in the correct section or not...If not Kindly guide me where to post this...

I am confused about what are normal modes of propagation in isotropic or anisotropic media?? or How one can define Normal modes?? Whether these are modes that propagate only with phase shift or is there any other defination...??

Many Thanks for the anticipated support and consideration

Takecare..
Taimoor...

 

[billiards]

Normal modes are the natural modes of vibration of a system, these are the modes which vibrate at the resonant frequency. (I haven't explained anything, just given some other words to help build associations.)

These are simply the modes at which a system will vibrate under an initial impulse and no further driving force.

For example a tuning fork has a normal mode of vibration which corresponds to a specific frequency, no matter how you hit the fork it will always vibrate at the specific frequency, that is its normal mode frequency.

 

[taimoortalpur]

Many Thanks For your humble reply. I understood the normal modes in physical medium and i am curious how they relate to normal modes of light propagation in anisotropic crystals.

The normal modes travel along principle axes for anisotropic case. Why along the principle axis?? and i am not sure how these are defined here?? Whether these Normal modes are related to natural frequency of the crystal or some how the orientation of the crystal (reciprocal lattice) or just modes that propagate with constant phase??. How the normal modes of light are related to the optical phonons of crystal vibrations.??
I also appreciate if only you refer me to some useful material...

Thanks...