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

201 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
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biotechnology

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