Adjunct Professor of Physics
Dr. Everitt is one of the Army's chief scientists. He works at the Army's Aviation and Missile RD&E Center at Redstone Arsenal, AL. Through his adjunct appointment in the Duke Physics Department, he leads an active experimental research group in condensed matter physics, nanophotonics, molecular physics, and novel terahertz imaging with colleagues on campus and through an international network of collaborators. Four principal research areas are being pursued:
1) Ultrafast Spectroscopy. This effort concentrates on the ultrafast spectroscopic characterization of wide bandgap semiconductor heterostructures and nanostructures. We use independently tunable pump and probe wavelengths that span the ultraviolet-visible-infrared regions from 200 nm to 12 microns with pulses shorter than 150 fs. The objective is to mapout and control carrier, exciton, and phonon transport and relaxation pathways in metal oxide and III-N semiconductors, sometimes doped with rare-earth atoms, using quantum efficiency, cw and time-resolved photoluminescence and differential transmission measurements. Areas of recent interest include characterization of efficient phosphorescence in sulfur-doped ZnO, carrier dynamics in III-N epilayers and multiple quantum wells, and characterization of radiative and nonradiative recombination of rare earth dopants in wide bandgap semiconductor hosts.
2) Ultraviolet Nanoplasmonics. Using metal nanoparticles to concentrate electromagnetic fields locally is an area of active research, most of which concentrates on using Au or Ag in the visible or near infrared spectral regions. Neither metal works in the ultraviolet, but there are significant advantages of extending plasmonics into the ultraviolet, including enhanced Raman cross sections, accelerated photo-degradation of toxins, and accelerated excitonic recombination. In partnership with Profs. April Brown (Duke ECE), Naomi Halas (Rice Univ.), Fernando Moreno (Univ. Cantabria), and others, we have been identifying and exploring new nanostructured metals including gallium and aluminum for ultraviolet plasmonics. We have recently demonstrated accelerated emission rates and surface enhanced Raman spectra in the ultraviolet.
3) Molecular Physics. The longest research effort involves the use of molecular rotational spectroscopy and time-resolved techniques to investigate molecular collision dynamics. These studies will help us develop more efficient terahertz sources, detect and identify clouds of trace gases, and understand nonequilibrium atmospheres and interstellar media. In collaboration with Prof. Frank De Lucia of Ohio State Univ., Dr. Everitt was the first to map out the complete rotational and vibrational energy transfer map of methyl fluoride, leading to the demonstration of a compact, tunable, coherent source of terahertz radiation for use in ground-based spectroscopy and astronomical observation. This double resonance technique has now been adapted as a new means for remotely identifying the constituents of a trace gas cloud at distances up to 1 km.
4) Terahertz Imaging. This newest activity uses powerful, cw, tunable millimeter- and submillimeter-wave sources to adapt various coherent imaging techniques to the terahertz spectral region. Interferometry, digital holography, tomography, synthetic aperture RADAR, ISAR, ellipsometry, and polarimetry are all explored to develop practical tools for non-destructive measurements of visually opaque materials. The lab contains a unique combination of tunable sources, Schottky diode detectors, heterodyne receivers, and bolometers, plus a one-of-a-kind THz beam characterization and imaging instrument. The lab also explores ways of optimizing and accelerating these slow imaging methodologies using digital reconstruction and compressive sampling techniques pioneered by on-campus collaborator Prof. David Brady and novel beam forming metamaterials with Prof. David Smith.
Lou, Minghe, et al. “Quantitative analysis of gas phase molecular constituents using frequency-modulated rotational spectroscopy.” The Review of Scientific Instruments, vol. 90, no. 5, May 2019, p. 053110. Epmc, doi:10.1063/1.5093912. Full Text
Li, Xueqian, et al. “Light-Induced Thermal Gradients in Ruthenium Catalysts Significantly Enhance Ammonia Production.” Nano Letters, vol. 19, no. 3, Mar. 2019, pp. 1706–11. Epmc, doi:10.1021/acs.nanolett.8b04706. Full Text
Kriisa, A., et al. “Cyclotron resonance in the high mobility GaAs/AlGaAs 2D electron system over the microwave, mm-wave, and terahertz- bands..” Scientific Reports, vol. 9, no. 1, Feb. 2019. Epmc, doi:10.1038/s41598-019-39186-2. Full Text
Gutiérrez, Y., et al. “Dielectric function and plasmonic behavior of Ga(II) and Ga(III).” Optical Materials Express, vol. 9, no. 10, Jan. 2019, pp. 4050–60. Scopus, doi:10.1364/OME.9.004050. Full Text
Wang, Fan, et al. “A high-efficiency regime for gas-phase terahertz lasers.” Proceedings of the National Academy of Sciences of the United States of America, vol. 115, no. 26, June 2018, pp. 6614–19. Epmc, doi:10.1073/pnas.1803261115. Full Text
Zhang, Xiao, et al. “Plasmon-Enhanced Catalysis: Distinguishing Thermal and Nonthermal Effects.” Nano Letters, vol. 18, no. 3, Mar. 2018, pp. 1714–23. Epmc, doi:10.1021/acs.nanolett.7b04776. Full Text
Gutiérrez, Yael, et al. “The UV Plasmonic Behavior of Distorted Rhodium Nanocubes.” Nanomaterials (Basel, Switzerland), vol. 7, no. 12, Dec. 2017. Epmc, doi:10.3390/nano7120425. Full Text
Karl, N., et al. “Characterization of an active metasurface using terahertz ellipsometry.” Applied Physics Letters, vol. 111, no. 19, Nov. 2017. Scopus, doi:10.1063/1.5004194. Full Text
Richard, J. T., and H. O. Everitt. “Millimeter Wave and Terahertz Synthetic Aperture Radar for Locating Metallic Scatterers Embedded in Scattering Media.” Ieee Transactions on Terahertz Science and Technology, vol. 7, no. 6, Nov. 2017, pp. 732–40. Scopus, doi:10.1109/TTHZ.2017.2757441. Full Text
Roberts, A., et al. “Probing electron-phonon interactions at the saddle point in graphene.” Laser Science, Ls 2014, 2014.
Golla, D., et al. “Time and energy resolved probing of many-body interactions in graphene and heterostructures.” Laser Science, Ls 2014, 2014.
Roberts, A., et al. “Probing electron-phonon interactions at the saddle point in graphene.” Optics Infobase Conference Papers, 2014.
Heimbeck, M. S., et al. “Terahertz digital holographic imaging of visibly opaque printed dielectrics.” International Conference on Infrared, Millimeter, and Terahertz Waves, Irmmw Thz, 2014. Scopus, doi:10.1109/IRMMW-THz.2014.6956276. Full Text
Roberts, A., et al. “Probing electron-phonon interactions at the saddle point in graphene.” Optics Infobase Conference Papers, 2014. Scopus, doi:10.1364/cleo_si.2014.sm3h.5. Full Text
Kung, P., et al. “Synthesis and optical properties of undoped and aluminum doped ZnO nanowires for optoelectronic nanodevice applications.” Proceedings 2014 Summer Topicals Meeting Series, Sum 2014, 2014, pp. 198–99. Scopus, doi:10.1109/SUM.2014.108. Full Text
Lo, M. K., et al. “Depth profiling of trimethylaluminum modified PET fibers with nanoscale infrared spectroscopy and imaging techniques.” Fiber Society 2014 Fall Meeting and Technical Conference: Fibers for ÃÂÃÂ¯ÃÂÃÂ¿ÃÂÃÂ½ the Future, 2014.
Lo, M. K., et al. “Depth profiling of trimethylaluminum modified PET fibers with nanoscale infrared spectroscopy and imaging techniques.” Fiber Society 2014 Fall Meeting and Technical Conference: Fibers for the Future, 2014.
Butler, L., et al. “Design, simulation, and characterization of THz metamaterial absorber.” Proceedings of Spie the International Society for Optical Engineering, vol. 8363, 2012. Scopus, doi:10.1117/12.919625. Full Text