Real-time observation of hidden multi-soliton dynamics in a few-cycle Ti:Sapph oscillator (Conference Presentation)

Mode-locked lasers are a prominent example of dissipative nonlinear systems which support soliton bound-states. However, rapid dynamic interactions between such soliton complexes with pico- to femtosecond separation are mostly invisible to standard laser characterization techniques, including scanning interferometric autocorrelation, temporally-averaged spectroscopy, and single-shot measurements at low repetition rates. Here, we apply the time-stretch dispersive Fourier transform (TS-DFT) and high-speed real-time sampling to resolve fast intracavity soliton dynamics. The multi-soliton complexes are induced in a common broadband commercial laser oscillator (~10 fs pulse width) by applying external perturbations. The optical spectrum of a multi-pulse complex corresponds to a spectral interferogram, encoding both the distances and the relative phase of its constituents. In order to access this information for fast bound-state dynamics, rapid spectral detection is essential. The presented single-shot spectroscopy is enabled via the transformation of spectral information to the time-domain via group-velocity-dispersion in a long optical fiber, and subsequent high-bandwidth real-time acquisition [1]. By recording such single-shot spectral interferograms, we can resolve a diverse set of dynamic bound-states, and identify unprecedented rapid dynamics of bound-states with regular, periodic and aperiodic behavior in a state-of-the-art broadband Kerr-lens oscillator. [1] G. Herink, B. Jalali, C. Ropers, D.R. Solli, "Resolving the buildup of femtosecond mode-locking with single-shot spectroscopy at 90 MHz frame-rate" Nat. Photon. 10, 321–326 (2016).