A5074531850- Mechanical and Optical Resonators
- Photonic and Optical Devices
- Strong Light-Matter Interactions
- Plasmonic and Surface Plasmon Research
- Topological Materials and Phenomena
- Terahertz technology and applications
- Thermal Radiation and Cooling Technologies
- Photonic Crystals and Applications
- Metamaterials and Metasurfaces Applications
- Advanced Thermoelectric Materials and Devices
- Carbon Nanotubes in Composites
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Ultrasonics and Acoustic Wave Propagation
- Photoacoustic and Ultrasonic Imaging
- Photorefractive and Nonlinear Optics
- Electronic and Structural Properties of Oxides
- Graphene research and applications
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Semiconductor Detectors and Materials
- Transition Metal Oxide Nanomaterials
- Advanced Condensed Matter Physics
- Laser Material Processing Techniques
- Neural Networks and Reservoir Computing
Rice University
2020-2025
Vanderbilt University
2016-2020
Perm State University
2013
PbTe crystals have a soft transverse optical phonon mode in the terahertz frequency range, which is known to efficiently decay into heat-carrying acoustic phonons, resulting anomalously low thermal conductivity. Here, we studied this via polarization-dependent spectroscopy. We observed softening of with decreasing temperature, indicative incipient ferroelectricity, explain through model including strong anharmonicity quartic displacement term. In magnetic fields up 25 T, splits two modes...
The recently demonstrated chiral modes of lattice motion carry angular momentum and therefore directly couple to magnetic fields. Notably, their moments are predicted be strongly influenced by electronic contributions. Here, we have studied the response transverse optical phonons in a set Pb 1− x Sn Te films, which is topological crystalline insulator for > 0.32 has ferroelectric transition at an -dependent critical temperature. Polarization-dependent terahertz magnetospectroscopy...
Creating artificial matter with controllable chirality in a simple and scalable manner brings new opportunities to diverse areas. Here we show two such methods based on controlled vacuum filtration - twist stacking mechanical rotation for fabricating wafer-scale chiral architectures of ordered carbon nanotubes (CNTs) tunable large circular dichroism (CD). By controlling the angle handedness twist-stacking approach, maximize CD response achieve high deep-ultraviolet ellipticity 40 ± 1 mdeg...
Abstract Hybrid material systems are a promising approach for extending the capabilities of silicon photonics. Given weak electro‐optic and thermo‐optic effects in silicon, there is intense interest integrating an ultrafast‐switching phase‐change with large refractive index contrast into waveguide, such as vanadium dioxide (VO 2 ). It well established that phase transition VO thin films can be triggered by ultrafast, 800 nm laser pulses, pump‐laser fluence critical determinant recovery time...
Lead telluride is an important thermoelectric material due to its large Seebeck coefficient combined with unusually low thermal conductivity that related the strong anharmonicity of phonons in this material. Here, we have studied resonant and nonperturbative coupling transverse optical lead cavity photons inside small-mode-volume metallic metasurface cavities photonic modes terahertz frequencies. We observed a giant vacuum Rabi splitting on order bare phonon Through time-domain spectroscopy...
Abstract Most commercial systems for ultraviolet-visible (UV–VIS), Fourier-transform infrared, circular dichroism (CD), and fluorescence spectroscopies are designed measurement of liquid samples. Moreover, adapters enabling the solid samples expensive or unavailable most instruments. Consequently, there is a significant need sample that enable both with single system. Here, we report two versions adapter cuvette can be used in spectroscopy instruments transmission One version techniques do...
Abstract Recent theoretical studies have highlighted how spatially varying cavity electromagnetic fields enable novel quantum electrodynamics phenomena, such as the Dicke superradiant phase transition. Three-dimensional photonic-crystal cavities, which exhibit discrete in-plane translational symmetry, overcome this limitation, but fabrication challenges hindered achievement of strong coupling. Here, we demonstrate multimode ultrastrong coupling between modes a three-dimensional at terahertz...
Carbon nanotubes (CNTs) possess extremely anisotropic electronic, thermal, and optical properties owing to their 1D character. While linear have been extensively studied, nonlinear processes, such as harmonic generation for frequency conversion, remain largely unexplored in CNTs, particularly macroscopic CNT assemblies. In this work, films of aligned type-separated (semiconducting metallic) CNTs are synthesized polarization-dependent third-harmonic (THG) from the with fundamental wavelengths...
Angle-resolved photoemission spectroscopy (ARPES) is a powerful tool for probing the momentum-resolved single-particle spectral function of materials. Historically, in situ magnetic fields have been carefully avoided as they are detrimental to control photoelectron trajectory during detection process. However, field an important experimental knob both and tuning symmetry-breaking phases electronic topology quantum In this paper, we introduce easily implementable method realizing tunable at...
In terahertz (THz) photonics, there is an ongoing effort to develop thin, compact devices such as dielectric photonic crystal (PhC) slabs with desirable light–matter interactions. However, previous works in THz PhC have been limited rigid substrates thicknesses <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mn>100</mml:mn> <mml:mspace width="thinmathspace"/> <mml:mi...
For facile manipulation of polarization states light for applications in communications, imaging, and information processing, an efficient mechanism is desired rotating with a minimum interaction length. Here, we report giant rotations terahertz (THz) electromagnetic waves ultrathin (~45 nm), high-density films aligned carbon nanotubes. We observed up to ~20{\deg} ~110{\deg} transmitted reflected THz pulses, respectively. The amount rotation was sensitive function the angle between incident...
Highly tunable light-matter hybrids, magnon polaritons, have been realized in an orthoferrite crystal driven by terahertz radiation external magnetic field. As the field is swept, a continuous transition from weak to strong coupling via exceptional point due magnetic-field-dependent strength observed.
Abstract Hybrid light–matter coupled states, or polaritons, in magnetic materials have attracted significant attention due to their potential for enabling novel applications spintronics and quantum information processing. However, most magnon‐polariton studies the strong coupling regime date been carried out ferromagnetic with magnon excitations at gigahertz frequencies. Here, resonant photon–magnon frequencies above 1 terahertz is investigated first time a prototypical room‐temperature...
Silicon carbide (SiC) is a promising material for new generation electronics including high power/high temperature devices and advanced optical applications such as room spintronics quantum computing. Both types of require the control defects particularly those created by ion bombardment. In this work, modification constants 4H-SiC due to hydrogen implantation at 180 keV fluences ranging from 1014 1016 cm−2 reported. The depth dependence modified was extracted coherent acoustic phonon...
The photoelastic phenomenon has been widely investigated as a fundamental elastooptical property of solids. This effect applied extensively to study stress distribution in lattice-mismatched semiconductor heterostructures. GaAs based optoelectronic devices (e.g. solar cells, modulators, detectors, and diodes) used space probes are subject damage arising from energetic proton (H+) irradiation. For that reason, the irradiation on coefficients is primary importance optoelectronics. However,...
A central problem in modern condensed matter physics is the understanding of materials with strong electron correlations. Despite extensive work, essential many these systems not understood and there very little ability to make predictions this class materials. In manuscript we share our personal views on major open problems field correlated systems. We discuss some possible routes progress rich fascinating field. This result vigorous discussions deliberations that took place at Johns...
Understanding the ultrafast carrier dynamics of graphene on a substrate is fundamental step in development based opto-electronic devices. Here, we present pump-probe measurements supported quartz for range pump fluences that enable us to observe both decreased and enhanced probe transmission regimes femtosecond timescale. Unexpectedly, at an intermediate fluence, order magnitude decrease relaxation time constant differential observed. By employing number different models interpret our...
Gallium phosphide is an important indirect band gap material with variety of applications in optics ranging from LEDs to GaP/Si based solar cells. We investigated GaP using ultrafast, pump-probe coherent acoustic phonon spectroscopy (time-domain Brillouin scattering). measured the dependence amplitude differential reflectivity as modulated by phonons (CAPs) a function laser probe energy and found that oscillations varies non-monotonically near direct transition at $\Gamma$ point. A...