# Optical kinks and kink-kink and kink-pulse interactions in resonant two-level media

## TL;DR

This paper investigates optical kinks in resonant two-level media, demonstrating their formation, self-similarity, and controllable interactions with other kinks and pulses through numerical simulations.

## Contribution

It introduces the concept of kinklike pulses, analyzes kink collisions and interactions, and shows how to control kink speed via counterpropagating field parameters.

## Key findings

- Kinks exhibit self-similarity during formation.
- Kink interactions can be controlled by field parameters.
- The phenomena extend to incoherent light-matter interactions.

## Abstract

An optical kink is a shock-wave-like field structure which can appear in a resonant two-level medium as a result of the nonlinear process of self-steepening. We numerically simulate this process using an adiabatically switching waveform as an input and confirm the self-similarity of resulting kinks. The analysis is also applicable to a more general waveform with a decaying trailing edge which we call a kinklike pulse. We study in detail collisions of kinks with other kinks and ultrashort pulses and demonstrate the possibility to control kink speed by changing the parameters of counterpropagating fields. The effects considered can be treated as belonging to a wide class of unexplored phenomena in the regime of incoherent light-matter interaction.