Recent News

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

  • By Huiling Shao
  • 19 March 2019

Check out our featured article from Jeremy Levy group on Lignt: Science & Applications. 

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.

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Peyman Givi will co-chair mini symposium at 17th International Conference on Numerical Combustion

  • By Huiling Shao
  • 19 March 2019

Peyman Givi, developer of the Filtered Density Function (FDF) used in very high fidelity numerical simulation of chemically reactive flow fields, will co-chair a mini symposium on the subject at the 17th International Conference on Numerical Combustion (NC19) in Aachen, Germany from May 6-8, 2019. The mini symposium “Filtered Density Function Methods for Turbulent Reactive Flows” will include 60 participants and 28 presented papers. According to Dr. Givi, participants will learn the latest developments and innovations in enhancing the computational and predictive capabilities of the FDF methodology.

Sangyeop Lee's Research on ab initio Phonon Thermal Transport Published in Materials Today Physics

  • By Huiling Shao
  • 12 March 2019

Sangyeop Lee is co-author of a recent article, “Survey of ab initio phonon thermal transport” in Materials Today Physics (vol. 7, 2018, pp. 106-120, DOI 10.1016/j.mtphys.2018.11.008). This article provides a comprehensive survey of first-principles Peierls-Boltzmann thermal transport as developed in the literature over the last decade, with particular focus on more recent advances. This review will demonstrate the wide variety of calculations accessible to first-principles transport methods (including dimensionality, pressure, and defects), highlight unusual properties and predictions that have been made, and discuss some challenges and behaviors that lie beyond.

Dr. Lee, who joined Pitt in 2015, studies nanoscale thermal transport in solid materials, and his research is currently focused on hydrodynamic phonon transport in graphitic materials and thermal transport in fully or partially disordered phase. His group utilizes Boltzmann transport theory, Green's function method, and molecular dynamics simulation, all of which use interatomic force constants calculated from density functional theory. He earned his BS and MS in mechanical and aerospace engineering from the Korea Advanced Institute of Science and Technology, and PhD in mechanical engineering from MIT. 

Written by Paul Kovach. 

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