# Nonlinear Spectroscopy and All-Optical Switching of Femtosecond Soliton Molecules

## TL;DR

This paper explores the nonlinear optical interactions and ultrafast control of soliton molecules, revealing their vibrational-like dynamics and demonstrating all-optical switching for potential applications in ultrafast information processing.

## Contribution

It introduces two-dimensional spectroscopy of soliton molecules, uncovers anharmonic interactions, and demonstrates all-optical switching between bound states in an optical oscillator.

## Key findings

- Resolved anharmonicities in soliton interactions
- Demonstrated all-optical switching of soliton states
- Identified overtone and sub-harmonic generation in soliton molecules

## Abstract

The emergence of confined structures and pattern formation are exceptional manifestations of concurring nonlinear interactions found in a variety of physical, chemical and biological systems[1]. Optical solitons are a hallmark of extreme spatial or temporal confinement enabled by a variety of nonlinearities. Such particle-like structures can assemble in complex stable arrangements, forming "soliton molecules"[2,3]. Recent works revealed oscillatory internal motions of these bound states, akin to molecular vibrations[4-8]. These observations beg the question as to how far the "molecular" analogy reaches, whether further concepts from molecular spectroscopy apply in this scenario, and if such intra-molecular dynamics can be externally driven or manipulated. Here, we probe and control such ultrashort bound-states in an optical oscillator, utilizing real-time spectroscopy and time-dependent external perturbations. We introduce two-dimensional spectroscopy of the linear and nonlinear bound-state response and resolve anharmonicities in the soliton interaction leading to overtone and sub-harmonic generation. Employing a non-perturbative interaction, we demonstrate all-optical switching between distinct states with different binding separation, opening up novel schemes of ultrafast spectroscopy, optical logic operations and all-optical memory.

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Source: https://tomesphere.com/paper/1908.04323