Article Title

Monolayer graphene as a saturable absorber in a mode-locked laser

Authors

Qiaoliang Bao, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
Han Zhang, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
Zhenhua Ni, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
Yu Wang, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
Lakshminarayana Polavarapu, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
Zexiang Shen, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
Qing-Hua Xu, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
Dingyuan Tang, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
Kian Ping Loh, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore

Keywords

Graphene, saturable absorber, laser, carrier dynamics, ultrafast photonics

Abstract

We demonstrate that the intrinsic properties of monolayer graphene allow it to act as a more effective saturable absorber for mode-locking fiber lasers when compared to multilayer graphene. The absorption of monolayer graphene can be saturated at lower excitation intensity compared to multilayer graphene, graphene with wrinkle-like defects, or functionalized graphene. Monolayer graphene has a remarkably large modulation depth of 65.9%, whereas the modulation depth of multilayer graphene is greatly reduced due to nonsaturable absorption and scattering loss. Picosecond ultrafast laser pulses (1.23 ps) can be generated using monolayer graphene as a saturable absorber. Due to the ultrafast relaxation time, larger modulation depth and lower scattering loss of monolayer graphene, it performs better than multilayer graphene in terms of pulse shaping ability, pulse stability, and output energy.

Graphical Abstract

DOI

https://doi.org/10.1007/s12274-010-0082-9

Publisher

Tsinghua University Press

Recommended Citation

Qiaoliang Bao,Han Zhang,Zhenhua Ni,Yu Wang,Lakshminarayana Polavarapu,Zexiang Shen,Qing-Hua Xu,Dingyuan Tang,Kian Ping Loh, Monolayer graphene as a saturable absorber in a mode-locked laser. NanoRes.2011, 4(3): 297–307