Boston College
Boston College Department of Physics
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Physics Department Personnel

Dr. Krzysztof Kempa

Professor of Physics

617-552-3592
Higgins Hall 230E
kempa@bc.edu

Education

  • Ph.D., Theoretical Physics, University of Wroclaw, Poland, 1980
  • M.S., Electrical Engineering: Semiconductor Technology, Technical University of Wroclaw, Poland, 1973

Areas of Research
My research is focused on nanostructures. Nanostructures are artificially grown or self assembled structures, with dimensions ranging from 1 to 100 nm. In these systems cross-dimensional behavior, as well as, crossover from quantum to classic phenomena, can be observed. Examples include semiconductor quantum structures (wells, wires and dots), carbon nano-materials (carbon nanotubes, bucky balls), and bio-molecules (DNA). Understanding of their rich physical and chemical properties may lead, through nanotechnology, to fascinating applications, and may also contribute to fundamental understanding of biological processes. I am trying to understand such systems by utilizing various theoretical schemes, including  computer simulations and modeling. This funded work is done in collaboration with students, other theorists and experimentalists. See details below.

Research

  • Discrete optics

    We have proposed a new field of optics, based on nanoantennas and nanocoaxial lines. These are metallic nanostructures which behave exactly like their radio technology counterparts: they can receive light, and transmit it through subwavelength channels. New effective media can be made based on these nanostructures, capable of various effects: negative refraction, subwave image resolution, wave conjugation, etc. Novel, high efficiency and low cost solar cells can be made using these media.


  • Photonic, polaritonic and plasmonic crystals

    We study properties of photonic, polaritonic and plasmonic crystals. These are periodic dielectric and/or metallic systems, in which photon, polariton or plasmon propagation is similar to electronic propagation in conventional crystals. In particular, formation of a band structure, analogous to that in solid state systems occurs. We have recently discovered the light flux switching in such crystals, which can be used in optoelectronic switches and bio-sensors. This research is relevant for many opto-electronic applications. Work is being done in collaboration with Z. Ren, and part of it is supported by grant from US Army Natick Soldier Center and NanoLab.


  • Carrier dynamics

    We study interaction of electrons (or holes) with other quasiparticles (electrons, holes, phonons, etc.), and with an electromagnetic radiation. We also study electromagnetic emission (including lasing) in current driven systems with strong electron-electron and electron-phonon interactions, in particular in the terahertz (THz) frequency range. In this context we study the possibility of a stimulated emission of plasmons (plasmon instability). This work has been done in collaboration with P. Bakshi, group of E. Gornik, and has been supported by a series of grants from US Army Research Office.


  • Composite nanomaterials

    By suspending nanostructures (such as carbon nanotubes) in a polymer or ceramic matrix, novel composite materials with unique mechanical and dielectric properties can be engineered. We study the correlation of properties of such materials with their nano-structure. Work is being done in collaboration with Z. Ren and supported by NanoLab.


  • Bio applications of nanostructures

    We have recently demonstrated that magnetically driven carbon nanotubes can be used as nano-vehicles capable of delivering bio-molecules to cells, at very high efficiency. We have also demonstrated that the conventional electroporation can be made be use of microwaves. This work has been done in collaboration with T. Chiles (BC Biology) and NanoLab.

Other Activity


Selected Publications

  • K. Kempa, X. Wang, Z. F. Ren, and M. J. Naughton, "Discretely Guided Electromagnetic Effective Medium," Appl. Phys. Lett. 92, 043114 (2008).
  • D. Cai, D. Blair, F. J. Dufort, M. R. Gumina, Zh. Huang, G. Hong, D. Wagner, D. Canahan, K. Kempa, Z. F. Ren, and T. C. Chiles, “Interaction Between Carbon Nanotubes and Mammalian Cells: Characterization by Flow Cytometry and Application,” Nanotechnology 19, 345102 (2008).
  • J.Y Huang, S .Chen, Z.F. Ren, Z. Wang, K. Kempa, M.J. Naughton, G. Chen, M. S. Dresselhaus, "Enhanced Ductile Behavior of Tensile-Elongated Individual Double-Walled and Triple-Walled Carbon Nanotubes at High Temperatures," Phys. Rev. Lett. 98(18), 185501 (2007).
  • J. Y. Huang, S. Chen, Z. Q. Wang, K. Kempa,Y. M. Wang, S. H. Jo, G. Chen, M. S. Dresselhaus, and Z. F. Ren, "Superplastic Carbon Nanotubes," Nature 439, 281 (2006).
  • J. Y. Huang, S. Chen, Z. F. Ren, G. Chen, and M. S. Dresselhaus, "Real-Time Observation of Tubule Formation from Amorphous Carbon Nanowires under High-Bias Joule Heating," Nano Lett. 6 (8), 1699–1705 (2006).
  • K. Kempa, R. Ruppin, and J. B. Pendry, “Electromagnetic Response of a Point-Dipole Crystal,” Phys. Rev. B 72, 205103 (2005); also featured in the November 14, 2005 issue of Virtual Journal of Nanoscale Science & Technology.
  • T. Kempa, D. Carnahan, M. Olek, M. Correa, M. Giersig, M. Cross, G. Benham, M. Sennett, Z.F. Ren, and K. Kempa, “Dielectric Media Based on Isolated Metallic Nanostructures,” J. Appl. Phys. 98, 034310 (2005). The paper was selected for the August 22, 2005 issue of Virtual Journal of Nanoscale Science & Technology.
  • D. Cai, J. Mataraza, Z. H. Qin, Z. Huang, J. Huang, T. C. Chiles, D. Carnahan, K. Kempa, Z.F. Ren, “Highly Efficient Molecular Delivery into Mammalian Cells Using Carbon Nanotube Spearing,” Nature Methods 2 (6), 449 (2005).
  • X. Wang and K. Kempa, “Negative Refraction and Subwavelength Lensing in a Polaritonic Crystal,” Phys. Rev. B 71, 233101 (2005).
  • Y. Wang, K. Kempa, B. Kimball, J. B. Carlson, G. Benham, W. Z. Li, T. Kempa, J. Rybczynski, A. Herczynski, and Z. F. Ren, “Receiving and Transmitting Light Like Radio Waves: Antenna Effect in Arrays of Aligned Carbon Nanotubes,” Appl. Phys. Lett. 85, 2607 (2004). Reported in Nature and Science News, AIP, CNN and ABC and more.
  • K. Kempa, Y. Zhou, J. R. Engelbrecht, P. Bakshi, H. I. Ha, J. Moser, M.J. Naughton, J. Ulrich, G. Strasser, E. Gornik, and K. Unterrainer, "Intersubband Transport in Quantum Wells in Strong Magnetic Fields Mediated by Single- and Two-Electron Scattering," Phys. Rev. Lett. 88, 226803 (2002).
  • K. Kempa, E. Gornik, K. Unterrainer, M. Kast, and G. Strasser, "Resonant Tunneling Mediated by Resonant Emission of Intersubband Plasmons," Phys. Rev. Lett. 86, 2850 (2001).
  • H.H. Weitering, X. Shi, P.D. Johnson, J. Chen, N.J. DiNardo, K. Kempa, "Mott Insulating Ground State on a Triangular Surface Lattice," Phys. Rev. Lett. 78, 1331 (1997).
  • Y. Zhao, D.C. Tsui, M. Santos, M. Shayegan, R.A. Ghanbari, D.A. Antoniadis, H. I . Smith, and K. Kempa, "Mode Softening in the Far-Infrared Excitation of Quantum-Wire Arrays," Phys. Rev. B 48, 5249 (1993).
  • K.D. Tsuei, E.W. Plummer, A. Liebsch, K. Kempa, P. Bakshi, "Multipole Plasmon Modes at a Metal Surface," Phys. Rev. Lett. 64, 44 (1990).


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