Large optical nonlinearity enabled by coupled metallic quantum wells

Haoliang Qian, Shilong Li, Ching Fu Chen, Su Wen Hsu, Steven Edward Bopp, Qian Ma, Andrea R. Tao, Zhaowei Liu

Research output: Contribution to journalLetterpeer-review

24 Citations (Scopus)


New materials that exhibit strong second-order optical nonlinearities at a desired operational frequency are of paramount importance for nonlinear optics. Giant second-order susceptibility χ (2) has been obtained in semiconductor quantum wells (QWs). Unfortunately, the limited confining potential in semiconductor QWs causes formidable challenges in scaling such a scheme to the visible/near-infrared (NIR) frequencies for more vital nonlinear-optic applications. Here, we introduce a metal/dielectric heterostructured platform, i.e., TiN/Al 2 O 3 epitaxial multilayers, to overcome that limitation. This platform has an extremely high χ (2) of approximately 1500 pm/V at NIR frequencies. By combining the aforementioned heterostructure with the large electric field enhancement afforded by a nanostructured metasurface, the power efficiency of second harmonic generation (SHG) achieved 10 −4 at an incident pulse intensity of 10 GW/cm 2 , which is an improvement of several orders of magnitude compared to that of previous demonstrations from nonlinear surfaces at similar frequencies. The proposed quantum-engineered heterostructures enable efficient wave mixing at visible/NIR frequencies into ultracompact nonlinear optical devices.

Original languageEnglish
Article number13
JournalLight: Science and Applications
Issue number1
Publication statusPublished - 2019 Dec 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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