Using n- and p-Type Bi2Te3 topological insulator nanoparticles to enable controlled femtosecond mode-locking of fiber lasers

Yung Hsiang Lin, Sheng Fong Lin, Yu Chieh Chi, Chung Lun Wu, Chih Hsien Cheng, Wei Hsuan Tseng, Jr-Hau He, Chih I. Wu, Chao Kuei Lee, Gong Ru Lin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

136 Scopus citations

Abstract

Mechanically triturated n- and p-type Bi2Te3 nanoparticles, the nanoscale topological insulators (TIs), are employed as nonlinear saturable absorbers to passively mode-lock the erbium-doped fiber lasers (EDFLs) for sub-400 fs pulse generations. A novel method is proposed to enable the control on the self-amplitude modulation (SAM) of TI by adjusting its dopant type. The dopant type of TI only shifts the Fermi level without changing its energy bandgap, that the n- and p-type Bi2Te3 nanoparticles have shown the broadband saturable absorption at 800 and 1570 nm. In addition, both the complicated pulse shortening procedure and the competition between hybrid mode-locking mechanisms in the Bi2Te3 nanoparticle mode-locked EDFL system have been elucidated. The p-type Bi2Te3 with its lower effective Fermi level results in more capacity for excited carriers than the n-type Bi2Te3, which shortens the pulse width by enlarging the SAM depth. However, the strong self-phase modulation occurs with reduced linear loss and highly nonsaturated absorption, which dominates the pulse shortening mechanism in the passively mode-locked EDFL to deliver comparable pulse widths of 400 and 385 fs with n- and p-type Bi2Te3 nanoparticles, respectively. The first- and second-order Kelly sidebands under soliton mode-locking regime are also observed at offset frequencies of 1.31 and 1.94 THz, respectively.

Original languageEnglish (US)
Pages (from-to)481-490
Number of pages10
JournalACS Photonics
Volume2
Issue number4
DOIs
StatePublished - Apr 15 2015

Keywords

  • Bi<inf>2</inf>Te<inf>3</inf> nanoparticle
  • femtosecond soliton laser
  • passive mode-locking
  • pulse compression
  • topological insulator

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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