Optical black hole lasers

TL;DR

This paper demonstrates through numerical simulations how optical black hole lasers can be realized, showing mode growth, burst emissions, and a new zero-frequency regime leading to lasing at zero frequencies.

Contribution

It introduces a novel optical black hole laser configuration and uncovers a zero-frequency mode regime that enhances amplification and modifies trapped light structures.

Findings

Mode growth inside the cavity with positive and negative frequencies

Periodic burst emissions corresponding to cavity round trips

Lasing at zero-frequency modes after long propagation

Abstract

Using numerical simulations we show how to realise an optical black hole laser, i.e. an amplifier formed by travelling refractive index perturbations arranged so as to trap light between a white and a black hole horizon. The simulations highlight the main features of these lasers: the growth inside the cavity of positive and negative frequency modes accompanied by a weaker emission of modes that occurs in periodic bursts corresponding to the cavity round trips of the trapped modes. We then highlight a new regime in which the trapped mode spectra broaden until the zero-frequency points on the dispersion curve are reached. Amplification at the horizon is highest for zero-frequencies, therefore leading to a strong modification of the structure of the trapped light. For sufficiently long propagation times, lasing ensues only at the zero-frequency modes.