Mode-locking based on a zero-area pulse formation in a laser with a coherent absorber

TL;DR

This paper demonstrates a novel mode-locking mechanism in a dye laser, where zero-area pulses are formed through coherent light-absorber interactions, differing from traditional saturation-based methods.

Contribution

It introduces a new mode-locking regime driven by coherent Rabi oscillations in a dye laser with iodine absorber cells, highlighting a different physical process from conventional methods.

Findings

Mode-locking observed in a dye laser with iodine absorber.

Zero-area pulses are formed via Rabi oscillations.

The mechanism differs from saturation-based mode-locking.

Abstract

We observe experimentally a mode-locking in a continuous narrow-band tunable dye laser with molecular iodine absorber cells, which transitions have large phase relaxation time T2. We show that the mode-locking arises due to coherent interaction of light with the absorbing medium leading to Rabi oscillations, so that zero-area (0{\pi}-) pulses in the absorber are formed. Such mode-locking regime is different to most typical passive modelocking mechanisms where saturation plays the main role.