Superlight inverse Doppler effect

Abstract

There is a century-old tenet [1, 2] that the inverse Doppler frequency shift of light [3-13] is impossible in homogeneous systems with a positive refractive index. Here we break this long-held tenet by predicting a new kind of Doppler effect of light inside the Cherenkov cone. Ever since the classic work of Ginzburg and Frank, it has been known that a superlight (i.e., superluminal) normal Doppler effect [14-18] appears inside the Cherenkov cone when the velocity of the source v is larger than the phase velocity of light v_p. By further developing their theory we discover that an inverse Doppler frequency shift will arise when v>2v_p. We denote this as the superlight inverse Doppler effect. Moreover, we show that the superlight inverse Doppler effect can be spatially separated from the other Doppler effects by using highly squeezed polaritons (such as graphene plasmons), which may facilitate the experimental observation.

arXiv comment17 pages, 4 figures

References in corpus (5)

• Spin-orbit interactions of light
• Polaritons in layered 2D materials
• All-angle negative refraction of highly squeezed plasmon and phonon polaritons in graphene-boron nitride heterostructures
• Reverse Doppler effect in backward spin waves scattered on acoustic waves
• Caustic graphene plasmons with Kelvin angle