Research

Light-Matter Interaction: Fundamental Physics and Device Applications

Our group investigates condensed matter using state-of-the-art spectroscopic techniques to drive, probe, and control charge, spin, and vibrational dynamics in modern materials such as nanomaterials and strongly correlated materials. Our experimental facilities include the RAMBO system — a unique mini-coil-based 30-T pulsed magnet system equipped with ultrafast and nononlinear optical spectroscopy setups. Some of our current interests include:

  • Matter driven out of equilibrium
  • Optics and photonics in quantum materials
  • Quantum optics in condensed matter
  • Dicke phenomena, especially in cavities
  • Quantum information processing and spintronics

Results of our research will lead to an increased understanding of non-equilibrium many-body dynamics in condensed matter as well as development of novel opto-electronic devices.

Below are some recent highlights of our research. Please see the Publications page to see a full list of our publications.

Recent Research Highlights:

N. Komatsu et al., “Groove-Assisted Global Spontaneous Alignment of Carbon Nanotubes in Vacuum Filtration,” Nano Letters (2020).  (abstract)

 W. Gao et al., “Macroscopically Aligned Carbon Nanotubes as a Refractory Platform for Hyperbolic Thermal Emitters,” ACS Photonics (2019).  (abstract)
X. Li et al., “Observation of Dicke Cooperativity in Magnetic Interactions,” Science (2018).  (abstract)Rice University scientists observed Dicke cooperativity in a magnetic crystal in which two types of spins, in iron (blue arrows) and erbium (red arrows), interacted with each other. The iron spins were excited to form a wave-like object called a spin wave; the erbium spins precessing in a magnetic field (B) behaved like two-level atoms. (Credit: Illustration by Xinwei Li/Rice University) W. Gao et al., “Modulation-Doped Multiple Quantum Wells of Aligned Single-Wall Carbon Nanotubes,” Nature Photonincs (2018).  (abstract)Rice University scientists used nanotube films and polarized light to strongly couple light and matter progressively and on demand at room temperature. Their discovery of exceptional points in the resulting polaritons could allow researchers to explore novel quantum technologies like advanced information storage or one-dimensional lasers. (Credit: Weilu Gao/Rice University)
X. Li et al., “Vacuum Bloch-Siegert Shift in Landau Polaritons with Ultrahigh Cooperativity,” Nature Photonics (2018).  (abstract)A simplified schematic shows the basic idea behind a Rice University experiment to detect a Bloch-Siegert shift in strongly coupled light and matter. In this illustration, a light field rotating in the opposite direction to an orbiting electron still interacts with the electron in a cavity, in this case the empty space between two mirrors. The influence of resonance on the counter-rotating element defines the shift. (Credit: Xinwei Li/Kono Lab at Rice University) K. Yanagi et al., “Intersubband Plasmons in the Quantum Limit in Gated and Aligned Carbon Nanotubes,” Nature Communications (2018).  (abstract)
Y. Harada et al., “Giant Terahertz-Wave Absorption by Monolayer Graphene in a Total Internal Reflection Geometry,” ACS Photonics  (2017).  (abstract) N. Komatsu et al., “Modulation-Doped Multiple Quantum Wells of Aligned Single-Wall Carbon Nanotubes,” Advanced Functional Materials (2017).  (abstract)
G. T. Noe II et al., “Single-Shot Terahertz Time-Domain Spectroscopy in Pulsed High Magnetic Fields,” Optics Express (2016).  (abstract) Q. Zhang et al., “Stability of High-Density Two-Dimensional Excitons against a Mott Transition in High Magnetic Fields Probed by Coherent Terahertz Spectroscopy,” Phys. Rev. Lett. (2016).  (abstract)
Q. Zhang et al., “Collective non-perturbative coupling of 2D electrons with high-quality-factor terahertz cavity photons,” Nature Physics (2016).  (abstract) X. He et al., “Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes,” Nature Nanotechnology (2016).  (abstract)
W. Gao et al., “Electroluminescence from GaAs/AlGaAs Heterostructures in Strong In-Plane Electric Fields: Evidence for k– and Real-Space Charge Transfer,” ACS Photonics (2015).  (abstract)W.Gao ACS Photonics K. Cong et al., “Superfluorescence from Photoexcited Semiconductor Quantum Wells: Magnetic Field, Temperature, and Excitation Power Dependence,” Physical Review B (2015).  (abstract, full text)cropped-kono-website-title.jpg
Q. Zhang et al., “Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases,” Physical Review Letters (2014).  (abstract, full text, arXiv) X. He et al., “Carbon Nanotube Terahertz Detector,” Nano Letters (2014).  (abstract, full text, Rice News)
Q. Zhang et al., “Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes,” Nano Letters (2013).  (abstract, full text, Rice News)
 J.-H. Kim, G. T. Noe II, et al., “Fermi-Edge Superfluorescence from a Quantum-Degenerate Electron-Hole Gas,” Scientific Reports (2013).  (abstract, full text, Rice News)
X. He et al., “Photothermoelectric p-n Junction Photodetector with Intrinsic Broadband Polarimetry Based on Macroscopic Carbon Nanotube Films,” ACS Nano  (2013).  (abstract, full text, Rice News) S. Nanot et al., “Broadband, Polarization-Sensitive Photodetector Based on Optically-Thick Films of Macroscopically Long, Dense, and Aligned Carbon Nanotubes,” Scientific Reports (2013).  (abstract, full text, Rice News)
E. H. Hároz et al., “Fundamental Optical Processes in Armchair Carbon Nanotubes” (Feature Article), Nanoscale (2013). (abstract, full text, Rice News) J.-H. Kim et al., “Coherent Phonons in Carbon Nanotubes and Graphene” (Invited Review Article), Chemical Physics (2013). (abstract, full text)

Single-Wall Carbon Nanotube (SWCNT) Assignment Table:

Sivarajan Chart for the electronic assignment of single-wall carbon nanotubes (SWCNTs). Most experimental data is for SWCNTs suspended in SDS. Each colored square represents a particular (n,m) species identified byn (left axis) and m (bottom axis).  The color (yellow, green, and blue) of each square indicates its respective electronic type (medium-gap semiconductor, small-gap semiconductor, and metal).  For each (n,m) species, the radial breathing mode (RBM) frequency (in cm^{−1})  and E_{11} resonance wavelength (in nm) are indicated. For semiconducting [(n − m) mod 3 = ±1] nanotubes, the E_{22} resonance wavelength (in nm) is also shown.  The red circle in the bottom left corner of some entries represents isoradial (n,m) pairs of identical diameters; the pairs are matched with the number “i” inside the red circle.  Values for E_{11} are taken from Ref. 1. Values for RBM frequency and E_{22} are taken Ref. 2.  Reproduced with permission, Copyright 2003, Ramesh Sivarajan. Updated by Erik H. Hároz on August 15, 2012.