Self-induced transparency mode-locking, and area theorem

TL;DR

This paper explores self-induced transparency mode-locking (CML) in lasers, developing a diagram technique to predict its regimes, showing potential for ultra-short pulses below phase relaxation time, and introducing super-CML regimes with complex pulse dynamics.

Contribution

It introduces a diagram technique for predicting CML regimes in two-section lasers and demonstrates conditions for stable, ultra-short pulse generation, including novel super-CML regimes.

Findings

CML can occur at the first laser threshold with large enough phase relaxation time.

CML regimes can be unconditionally stable.

Existence of super-CML regimes with multiple Rabi oscillations.

Abstract

Self-induced transparency mode-locking (or coherent mode-locking, CML) which is based on intracavity self-induced transparency soliton dynamics, allows potentially to achieve nearly single cycle intracavity pulse durations, much below the phase relaxation time $T_2$ in a laser, which, despite of great promise, has not yet been realized experimentally. We develop a diagram technique which allows to predict the main features of CML regimes in a generic two-section laser. We show that CML can arise directly at the first laser threshold if the phase relaxation time is large enough. Furthermore, CML regimes can be unconditionally stable. We also predict the existence of ``super-CML regimes``, with a pulse coupled to several Rabi oscillations in the nonlinear medium.