Enhancement and electric charge-assisted tuning of nonlinear light generation in bipolar plasmonics

Wei Ding, Liangcheng Zhou, Stephen Y. Chou

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


We propose and experimentally demonstrate a new plasmonic nonlinear light generation (NLG) structure, termed plasmonic-enhanced, charge-assisted second-harmonic generator (p-CASH), that not only achieves high second-harmonic generation (SHG) enhancement (76-fold), large SHG tunability by bias (8%/V), wide tuning range (280%), 7.8 × 10-9 conversion efficiency, and high stability but also exhibits a SHG tuning, that is bipolar rather than unipolar, not due to the third-order nonlinear polarization term, hence fundamentally different from the classic electric field induced SHG-tuning (EFISH). We propose a new SHG tuning mechanism: the second-order nonlinear polarization term enhanced by plasmonic effects, changed by charge injection and negative oxygen vacancies movement, and is nearly 3 orders of magnitude larger than EFISH. p-CASH is a bipolar parallel-plate capacitor with thin layers of plasmonic nanostructures, a TiOx (semiconductor and nonlinear) and a SiO 2 (insulator) sandwiched between two electrodes. Fabrication of p-CASH used nanoimprint on 4″ wafer and is scalable to wallpaper-sized areas. The new structure, new properties, and new understanding should open up various new designs and applications of NLG in various fields.

Original languageEnglish (US)
Pages (from-to)2822-2830
Number of pages9
JournalNano Letters
Issue number5
StatePublished - May 14 2014

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Materials Science


  • Plasmonics
  • large area
  • nanoimprint
  • nanostructure
  • nonlinear light generation
  • second harmonic generation


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