Optical black hole lasers

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 zerofrequency modes.

Nonlinear optics of fibre event horizons

“…Indeed, although the initial observations were made in the context of light propagation in optical fibre 1 , similar ideas have subsequently been explored also in other optical systems 3,9 . Of course, analogies should always be applied with care, as perturbative physical effects present in one system may not always possess a clear counterpart in the other.…”

“…This picture not only suggests interesting links with general relativity 1,3,4,8,9 , but the underlying dynamics have also been postulated to influence the formation of optical rogue waves 7,11,12 , and to allow for the realization of optical functionalities such as the all-optical transistor 5 .…”

“…In a dispersive medium, such as an optical fibre, a change in velocity must be associated with a change in frequency, which has been attributed to the conservation of the Doppler shifted probe frequency 1,8 . This allows signatures of horizon dynamics to be identified in the probe spectrum, where frequency up-conversion (blue-shift) occurs at a white-hole horizon, and frequency downconversion (red-shift) occurs at a black-hole horizon 1,4,6,9 . Of course, the time-and frequency-domain descriptions represent an identical physics; a change in probe velocity can be equally understood to arise from the generation of new frequencies, linking the dynamics of fibre event horizons to the realm of nonlinear optical frequency conversion [14][15][16] .…”

Observation of an optical event horizon in a silicon-on-insulator photonic wire waveguide

“…Among others, we can cite studies involving cross-phase modulation (XPM) effects [1][2][3][4], or four wave mixing processes [3][4][5][6][7]. Recently, it has been shown that some of these interactions can mimic, under some circumstances, the interactions occurring at the horizons of black and white holes [8][9][10][11]. These so-called optical event horizons occur when an intense pulse, propagating in a nonlinear waveguide, prevents a weak probe wave traveling at a different velocity from passing through it.…”

Lasing on nonlinear localized waves in curved geometry

“…Studies on the effect of geometry on wave propagation can be tracked back to Lord Rayleigh in the early theory of sound [1], and extend to recent investigation as, for example, analogs of gravity in Bose-Einstein condensates [2], optical event horizon in fiber solitons [3,4], Anderson localization [5], random lasing [6] and celestial mechanics in metamaterials with transformation optics [7][8][9][10]. In addition to linear optics in curved space [11], geometrical constraints affect shape preserving wave packets, including localized solitary waves [12], extended Airy beams [13], and shock waves [14,15].…”