Quantum vacuum emission from a refractive-index front

Abstract

A moving boundary separating two otherwise homogeneous regions of a dielectric is known to emit radiation from the quantum vacuum. An analytical framework based on the Hopfield model, describing a moving refractiveindex step in 1 + 1 dimensions for realistic dispersive media has been developed by S. Finazzi and I. Carusotto [Phys. Rev. A 87, 023803 (2013)]. We expand the use of this model to calculate explicitly spectra of all modes of positive and negative norms. Furthermore, for lower step heights we obtain a unique set of mode configurations encompassing black-hole and white-hole setups. This leads to a realistic emission spectrum featuring black-hole and white-hole emission for different frequencies. We also present spectra as measured in the laboratory frame that include all modes, in particular a dominant negative-norm mode, which is the partner mode in any Hawking-type emission. We find that the emission spectrum is highly structured into intervals of emission with black-hole, white-hole, and no horizons. Finally, we estimate the number of photons emitted as a function of the step height and find a power law of 2.5 for low step heights.

The influence of spacetime curvature on quantum emission in optical analogues to gravity

“…Light under the step is slowed by the increased index, i.e., light of some frequencies will be slowed below the pulse speed and captured into the RIF. This is in analogy with the kinematics of waves around a black-hole event horizon [3,41,42]. At other frequencies, however, light follows different kinematic scenarios (i.e., trajectories of waves).…”

Optical analogue gravity physics: resonant radiation

“…There also exist the technologies to allow us to extract and manipulate individual emitted quanta, and the possibility to reduce the optical and thermal backgrounds to levels which allow sensitivity to the single particle, important for detecting weak effects. In addition to these experimental capabilities, there exist recent theoretical calculations to support analogue gravity in optical systems [10][11][12][13][14][15][16]. In this paper, we will focus on the fibre-optical scheme for analogue gravity.…”

Front-induced transitions

“…4(e). Fronts were also predicted to emit an analog of Hawking radiation in optical fiber waveguides 24,57,58 , cavities 30 , or ultrashort laser pulse filaments 88 .…”

“…Concepts of front induced transitions (FITs) are proposed and realized for frequency manipulation 23,24,35,36,41,43 , light stopping and optical delays 54,55 , bandwidth/time duration manipulation 30,32,52,53,56 . Reflective FITs can also represent an optical analog of an event horizon 24,25,35,36,43 and are predicted to emit an analog of Hawking radiation 24,30,57,58 . Light trapping by FIT leads to a so called optical push broom effect 30,52,53,59 , where signal pulse can be collected inside the front.…”