Atomic layer graphene as saturable absorber for ultrafast pulsed lasers

TL;DR

This paper demonstrates that atomic layer graphene can serve as an effective saturable absorber in fiber lasers, enabling ultrashort pulse generation with tunable properties and highlighting its potential as a versatile optical element.

Contribution

It introduces the use of monolayer graphene as a saturable absorber in fiber lasers, showing tunable modulation depth and ultrafast pulse generation.

Findings

Generated 756 fs soliton pulses at telecommunication wavelengths

Tunable modulation depth from 66.5% to 6.2% by varying graphene thickness

Graphene exhibits ultrafast recovery and wideband tunability as a laser mode locker

Abstract

The optical conductance of monolayer graphene is defined solely by the fine structure constant. The absorbance has been predicted to be independent of frequency. In principle, the interband optical absorption in zero-gap graphene could be saturated readily under strong excitation due to Pauli blocking. Here, we demonstrate the use of atomic layer graphene as saturable absorber in a mode-locked fiber laser for the generation of ultrashort soliton pulses (756 fs) at the telecommunication band. The modulation depth can be tuned in a wide range from 66.5% to 6.2% by varying the thickness of graphene. Our results suggest that ultrathin graphene films are potentially useful as optical elements in fiber lasers. Graphene as a laser mode locker can have many merits such as lower saturation intensity, ultrafast recovery time, tunable modulation depth and wideband tuneability.