|MadSci Network: Physics|
I have read the journal article titled, Reversed Doppler Effect in Photonic Crystals written by Evan J. Reedm Marin Soljacic, and John D. Joannopoulos (Physical Review letters, Volume 91, Number 13, 26 September 2003), in which they describe a new method of changing the frequency of light by using a shockwave in a photonic crystal. Basically, they use a dielectric with a high strain dependence, and create a crystal with a band gap above the frequency of the incident light. As the shockwave propagates through the crystal the dielectric constant is changed the the band gap is shifted into the frequency range. This creates a moving reflector in the crystal, capable of "doppler" shifting the frequency to a lower frequency. My question is, depending on the choice of dielectric material, this down shift in frequency can be accomplished with the shockwave moving in either direction, how is conservation of energy maintained? Is the energy from the frequency shifted light transfered to the shockwave? How is energy conserved in both shockwave directions?
Re: conservation in reversed doppler effects in photonic crystals?
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