Shock waves in crystals and frequency changes

[Tyro]

Shock waves propagating in photonic crystals can be used to lower or raise the frequency of light passing through them.

It seems (to me) to be some kind of Doppler effect at work here. The electrons in the atoms of the crystal absorb the light, and as they move because of the propagating shock wave, they emit the photon, which then experiences a Doppler shift.

Can anyone confirm this hypothesis, or is there another explanation for this? Would a similar, if less noticeable, but equally less destructive effect, be visible (watch the pun ) if sound waves were used in photonic crystals propagating light?

 

[futz]

Here is a preprint of the paper which was submitted to PRL. It's quite technical, but a good read nonetheless.

http://ab-initio.mit.edu/photons/shocked_PC/shock_paper.pdf

 

[Graeme Robinson]

Your hypothesis is correct, the phenomenon of frequency changes in photonic crystals due to shock waves is indeed a result of the Doppler effect. As the shock wave propagates through the crystal, it causes the atoms to vibrate and move, which in turn affects the frequency of the light passing through. This can result in a shift towards higher or lower frequencies depending on the direction of the shock wave and the arrangement of the crystal lattice.

In terms of sound waves, the effect would be less noticeable as sound waves have a much lower frequency compared to light waves. However, it is possible to observe similar frequency changes in photonic crystals when sound waves are used, although the effect would be less significant. This is because the atoms in the crystal would vibrate at a much lower frequency, resulting in a smaller Doppler shift.

Overall, the use of shock waves in photonic crystals to manipulate the frequency of light is a fascinating application of the Doppler effect and has potential for various technological advancements. Thank you for bringing up this interesting topic.