Over 100-THz bandwidth selective difference frequency generation at LaAlO3/SrTiO3 nanojunctions

Lu Chen; Erin Sutton; Hyungwoo Lee; Jung-Woo Lee; Jianan Li; Chang-Beom Eom; Patrick Irvin; Jeremy Levy

doi:10.1038/s41377-019-0135-0

Over 100-THz bandwidth selective difference frequency generation at LaAlO₃/SrTiO₃ nanojunctions

Light Sci Appl. 2019 Feb 27:8:24. doi: 10.1038/s41377-019-0135-0. eCollection 2019.

Authors

Lu Chen^{1

2}, Erin Sutton^{1

2}, Hyungwoo Lee³, Jung-Woo Lee³, Jianan Li^{1

2}, Chang-Beom Eom³, Patrick Irvin^{1

2}, Jeremy Levy^{1

2}

Affiliations

¹ 1Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 USA.
² Pittsburgh Quantum Institute, Pittsburgh, PA 15260 USA.
³ 3Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WA 53706 USA.

Abstract

The ability to combine continuously tunable narrow-band terahertz (THz) generation that can access both the far-infrared and mid-infrared regimes with nanometer-scale spatial resolution is highly promising for identifying underlying light-matter interactions and realizing selective control of rotational or vibrational resonances in nanoparticles or molecules. Here, we report selective difference frequency generation with over 100 THz bandwidth via femtosecond optical pulse shaping. The THz emission is generated at nanoscale junctions at the interface of LaAlO₃/SrTiO₃ (LAO/STO) that is defined by conductive atomic force microscope lithography, with the potential to perform THz spectroscopy on individual nanoparticles or molecules. Numerical simulation of the time-domain signal facilitates the identification of components that contribute to the THz generation. This ultra-wide-bandwidth tunable nanoscale coherent THz source transforms the LAO/STO interface into a promising platform for integrated lab-on-chip optoelectronic devices with various functionalities.