Emission by dielectric with oscillating refractive index

Abstract

We consider the two-photon emission by a dielectric where refractive index n oscillates in time. The oscillations of n cause analogous oscillations of the optical length. The velocity of the latter oscillations, in principle, may be arbitrarily large. If the maximal velocity of these oscillations V is much less than the light velocity c then the intensity of the emission will increase with V. However, if it strongly exceeds c then the opposite dependence takes place as the zero-point fluctuations cannot appreciably react on such a fast oscillations. Therefore, the crossover for the dependence of the emission on V exists at Vr ∼ c and a resonant enhancement of it is observed at this value of V. Our calculation gives Vr ≈ 3c. © 2005 IOP Publishing Ltd.