Experimental Evidence for Soliton Explosions

Abstract

We show, experimentally and numerically, that Ti:sapphire mode-locked lasers can operate in a regime in which they intermittently produce exploding solitons. This happens when the laser operates near a critical point. Explosions happen spontaneously, but external perturbations can trigger them. In stable operation, all explosions have similar features, but are not identical. The characteristics of the explosions depend on the intracavity dispersion.

Exploding soliton and front solutions of the complex cubic–quintic Ginzburg–Landau equation

“…These were found in numerical simulations [8,9] and their existence has been experimentally confirmed in a passively mode-locked solid state laser [10]. These solitons possess the interesting property of exploding at a certain point, breaking down into multiple pieces, and subsequently recovering their original shape.…”

“…The essential features of explosions, observed both theoretically [8,9] and experimentally [10], are: (1) Explosions occur intermittently. In the continuous model, they happen more or less regularly, but the period changes dramatically with a change of parameters.…”

Observation of soliton explosions in a passively mode-locked fiber laser

“…This is presumably because the explosions correspond to fleeting transients amidst an ultrafast train of pulses; capturing them requires real-time spectral and temporal diagnostics of a megahertz pulse train. So far only one experimental observation has been reported [11]. In this work Cundiff et al spectrally dispersed the output of a solid-state, Kerr-lens mode-locked Ti:Sapphire laser across a 6-element detector array, and measured the corresponding temporally resolved spectrum.…”

“…Figure 2(a) concatenates 100 experimentally measured single-shot spectra of consecutive pulses emitted by the laser, and we can immediately identify clear signatures [11] of soliton explosions. Specifically, when an explosion occurs, the spectrally broad dissipative soliton collapses into a narrower spectrum with higher amplitude, but after a few roundtrips returns back to its previous state until another explosion occurs.…”

“…The lack of observations in any other laser configuration raises significant questions pertaining to the experimental ubiquity of the phenomenon: do soliton explosions only manifest themselves in the particular anomalous-dispersion, spatially extended oscillator of ref. [11]? Compounded by the fact that only spectral signatures have been observed so far, it is clear that significant experimental efforts with high-resolution real-time diagnostics are required to fully understand this phenomenon.…”