Department of Physics | West Virginia University

Office of the Chair
P.O. Box 6315, 209 Hodges Hall
Morgantown, WV 26506-6315
PHONE: (304) 293-3422
FAX: (304) 293-5732

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Larry Halliburton
Professor
B.S., University of Missouri-Columbia, 1965
Ph.D., University of Missouri-Columbia, 1971

West Virginia University
Department of Physics
P. O. Box 6315
Morgantown, WV 26506

Tel: (304) 293-3422, ext. 1442
Fax: (304) 293-5732
lhallibu@wvu.edu

Nearly all solid-state lasers operate at discrete frequencies in the near-infrared region of the spectrum (typically in the 0.65 to 2.1 µm range). Also, a few tunable solid-state lasers operate in the near infrared (for example, Ti-sapphire operating from 0.67 to 0.98 µm and Co:MgF 2 operating from 1.8 to 2.5 µm). This, however, leaves significant portions of the spectrum without direct laser coverage. To fill these gaps in the near-ultraviolet, visible, near-infrared, and mid-infrared, scientists and engineers have turned to nonlinear optical materials. Harmonic generation, sum- and difference-frequency generation, and optical parametric oscillation can be initiated in a nonlinear optical material by pumping with a fixed wavelength laser. Optical parametric oscillators are especially important because they can be continuously tuned over wide wavelength ranges.

My current research includes studies of KTiOPO 4 (or KTP for short). This crystal has proven to be unusually versatile in frequency conversion applications throughout the visible and near-infrared, e.g., both as an harmonic generator and as an optical parametric oscillator. However, a major problem arises in many of its applications when very high laser powers are present. In frequency doubling, where an intense pump laser is needed to achieve high conversion efficiencies, gray tracks may form along the path of the pump beam. These gray tracks then absorb a portion of the pump beam and continued operation leads to catastrophic damage of the KTP crystal. The source of this optical" damage is extrinsic electron and hole traps within the crystal.

I and my students are exploring the basic mechanisms that lead to the formation of electrons and holes by sub-band-gap laser light in KTP crystals and we are identifying the traps that stabilize them (for periods of time from seconds to days). Spectroscopic techniques used to characterize these optically active point defects include magnetic resonance (EPR and ENDOR), optical absorption (UV, visible, and near IR),and luminescence (photo-, thermal-, and x-ray-induced). My laboratory has significant interaction with scientists in industry that either grow these KTP crystals or use them in devices.

Additional nonlinear optical materials are presently being investigated in my laboratory. These include ZnGeP 2 and CdGeAs 2 (in collaboration with Sanders, a Lockheed Martin Company in Nashua, NH), KH 2PO 4 (in collaboration with Lawrence Livermore National Laboratory), and LiB 3O 5 and BaB 2O 4 (in collaboration with Lightwave Electronics in Mountain View, CA).

Recent Publications

K. T. Stevens, N. Y. Garces, Lihua Bai, N. C. Giles, L. E. Halliburton, S. D. Setzler, P. G. Schunemann, T. M. Pollak, R. K. Route, and R. S. Feigelson, "Optical absorption and electron-nuclear double resonance study of Ni+ ions in AgGaSe2," accepted by Journal of Physics: Condensed Matter.

Wei Hong, L. E. Halliburton, D. Perlov, K. T. Stevens, R. K. Route, and Feigelson, "Observation of paramagnetic point defects in BBO (–BaB2O4) crystals," accepted by Optical Materials.

Lijun Wang, N. Y. Garces, L. E. Halliburton, and N. C. Giles, "Determination of the nitrogen acceptor ionization energy in zinc oxide by photoluminescence spectroscopy," accepted by Materials Research Society Symposium Proceedings.

N. Y. Garces, N. C. Giles, L. E. Halliburton, K. Nag ashio, R. S. Feigelson, and P. G. Schunemann, "Electron paramagnetic resonance of Cr2+ and Cr4+ ions in CdGeAs2 crystals," Journal of Applied Physics 94, 7567 (2003).

M. M. Chirila, N. Y. Garces, L. E. Halliburton, S. G. Demos, T. A. Land, and H. B. Radousky, "Production and thermal decay of radiation-induced point defects in KD2PO4 crystals," Journal of Applied Physics 94, 6456 (2003).

W. Hong, D. Perlov, and L. E. Halliburton, "Electron paramagnetic resonance study of Ag0 atoms and Ag2+ ions in –BaB2O4 nonlinear optical crystals," Journal of Physics D: Applied Physics 36, 2605 (2003).

Wei Hong, M. M. Chirila, N. Y. Garces, L. E. Halliburton, D. Lupinski, and P. Villeval, "Electron paramagnetic resonance and electron-nuclear double resonance study of trapped-hole centers in LiB3O5 crystals," Physical Review B 68, 094111/1-9 (2003).

Wei Hong, L. E. Halliburton, K. T. Stevens, D. Perlov, G. C. Catella, R. K. Route, and Feigelson, "Electron paramagnetic resonance study of electron and hole traps in –BaB2O4 (BBO) crystals," Journal of Applied Physics 94, 2510 (2003).

N. Y. Garces, L. Wang, N. C. Giles, L. E. Halliburton, D. C. Look, and D. C. Reynolds, "Thermal diffusion of lithium acceptors into ZnO crystals," Journal of Electronic Materials 32, 766 (2003).

M. M. Chirila, N. Y. Garces, L. E. Halliburton, D. R. Evans, R. K. Route, and M. M. Fejer, "Thermally stimulated luminescence from vapor-transport-equilibrated LiTaO3 crystals," Journal of Applied Physics 94, 301 (2003).

N. Y. Garces, Lijun Wang, N. C. Giles, L. E. Halliburton, G. Cantwell, and D. B. Eason, "Molecular nitrogen (N2) acceptors and isolated nitrogen (N) acceptors in ZnO crystals," Journal of Applied Physics 94, 519 (2003).

S. D. Setzler, K. T. Stevens, N. C. Fernelius, M. P. Scripsick, G. J. Edwards, and L. E. Halliburton, "Electron paramagnetic resonance and electron-nuclear double resonance of Ti3+ Centers in KTiOPO4," Journal of Physics: Condensed Matter 15, 3969 (2003).

N. Y. Garces, M. M. Chirila, H. J. Murphy, J. W. Foise, E. A. Thomas, C. Wicks, K. Grencewicz, L. E. Halliburton, and N. C. Giles, "Absorption, luminescence, and electron paramagnetic resonance of molybdenum ions in CdWO4," Journal of Physics and Chemistry of Solids 64, 1195 (2003).

N. Y. Garces, L. Wang, M. M. Chirila, L. E. Halliburton, and N. C. Giles, "Luminescence and EPR study of lithium-diffused ZnO crystals," Materials Research Society Symposium Proceedings 744, 87 (2003).

L. Bai, N. Y. Garces, N. Yang, P. G. Schunemann, S. D. Setzler, T. M. Pollak, L. E. Halliburton, and N. C. Giles, "Optical and EPR study of defects in cadmium germanium arsenide," Materials Research Society Symposium Proceedings 744, 537 (2003).

K. T. Stevens, L. E. Halliburton, S. D. Setzler, P. G. Schunemann, and T. M. Pollak, "Electron paramagnetic resonance and electron-nuclear double resonance study of the neutral copper acceptor in ZnGeP2 crystals," Journal of Physics: Condensed Matter 15, 1625 (2003).

D. C. Look, R. L. Jones, J. R. Sizelove, N. Y. Garces, N. C. Giles, and L. E. Halliburton, "The path to ZnO devices: donor and acceptor dynamics," Physica Status Solidi (a) 195, 171 (2003).

M. M. Chirila, N. Y. Garces, L. E. Halliburton, D. R. Evans, S. A. Basun, R. S. Meltzer, W. M. Yen, S. A. Rutkowski, D. Shumov, and J. S. Cahill, "Thermoluminescence study of stoichiometric LiNbO3 crystals," Journal of Applied Physics 92, 1221 (2002).

N. Y. Garces, L. Wang, L. Bai, N. C. Giles, L. E. Halliburton, and G. Cantwell, "Role of copper in the green luminescence from ZnO crystals," Applied Physics Letters 81, 622 (2002).

N. Y. Garces, N. C. Giles, L. E. Halliburton, G. Cantwell, D. B. Eason, D. C. Reynolds, and D. C. Look, "Production of nitrogen acceptors in ZnO by thermal annealing," Applied Physics Letters 80, 1334 (2002).

N. Y. Garces, L. E. Halliburton, K. T. Stevens, M. Shone, and G. K. Foundos, "Identification of silicon as the dominant hole trap in YVO4 crystals," Journal of Applied Physics 91, 1354 (2002).

N. Y. Garces, K. T. Stevens, L. E. Halliburton, M. Yan, N. P. Zaitseva, and J. J. DeYoreo, "Optical absorption and electron paramagnetic resonance of Fe ions in KDP crystals," Journal of Crystal Growth 225, 435 (2001).

N. Y. Garces, K. T. Stevens, L. E. Halliburton, S. G. Demos, H. B. Radousky, and N. P. Zaitseva, "Identification of electron and hole traps in KH2PO4 crystals," Journal of Applied Physics 89, 47 (2001).

K. T. Stevens, L. E. Halliburton, M. Roth, N. Angert, and M. Tseitlin, "Identification of a Pb-related Ti3+ center in flux-grown KTiOPO4," Journal of Applied Physics 88, 6239 (2000).

M. M. Chirila, N. Y. Garces, H. J. Murphy, C. Wicks, K. Grencewicz, L. E. Halliburton, and N. C. Giles, "Identification of trapping sites for OH molecular ions in CdWO4," Journal of Physics and Chemistry of Solids 61, 1871 (2000).

N. Y. Garces, K. T. Stevens, and L. E. Halliburton, "Electron paramagnetic resonance of platinum impurities in KTiOPO4 crystals," Journal of Applied Physics 87, 8682 (2000).

M. Moldovan, K. T. Stevens, L. E. Halliburton, P. G. Schunemann, T. M. Pollak, S. D. Setzler, and N. C. Giles, "Photoluminescence and EPR of phosphorus vacancies in ZnGeP2," Materials Research Society Symposium Proceedings 607, 445 (2000).

K. T. Stevens, S. D. Setzler, P. G. Schunemann, T. M. Pollak, N. C. Giles, and L. E. Halliburton, "Photoinduced changes in the charge states of native donors and acceptors in ZnGeP2," Materials Research Society Symposium Proceedings 607, 379 (2000).

S. D. Setzler, P. G. Schunemann, T. M. Pollak, M. C. Ohmer, J. T. Goldstein, F. K. Hopkins, K. T. Stevens, L. E. Halliburton, and N. C. Giles, "Characterization of defect-related optical absorption in ZnGeP2," Journal of Applied Physics 86 , 6677 (1999).

H. J. Murphy, K. T. Stevens, N. Y. Garces, M. Moldovan, N. C. Giles, and L. E. Halliburton, "Optical and EPR characterization of point defects in bismuth-doped CdWO4 crystals," Radiation Effects and Defects in Solids 149, 273 (1999).

K. T. Stevens, N. Y. Garces, L. E. Halliburton, M. Yan, N. P. Zaitseva, J. J. DeYoreo, G. C. Catella, and J. R. Luken, "Identification of the intrinsic self-trapped hole center in KD2PO4," Applied Physics Letters 75, 1503 (1999).

S. D. Setzler, N. C. Giles, L. E. Halliburton, P. G. Schunemann, and T. M. Pollak, "Electron paramagnetic resonance of a cation antisite defect in ZnGeP2," Applied Physics Letters 74, 1218 (1999).

K. T. Stevens, S. D. Setzler, L. E. Halliburton, M. P. Scripsick, and J. Rottenberg, "Role of silicon impurities in the trapping of holes in KTiOPO4 crystals," Journal of Applied Physics 85, 1063 (1999).

C. I. Rablau, S. D. Setzler, L. E. Halliburton, F. P. Doty, and N. C. Giles, "PL and EPR spectroscopy of point defects in detector grade Cd1-xZnxTe," Materials Research Society Symposium Proceedings 487, 71 (1998).

K. T. Stevens, S. D. Setzler, L. E. Halliburton, N. C. Fernelius, P. G. Schunemann, and T. M. Pollak, "Electron-nuclear double resonance study of the zinc vacancy in zinc germanium phosphide (ZnGeP2)," Materials Research Society Symposium Proceedings 484, 549 (1998).

C. I. Rablau, S. D. Setzler, L. E. Halliburton, N. C. Giles, and F. P. Doty, "Point defects in Cd1-xZnxTe: A correlated photoluminescence and EPR study," Journal of Electronic Materials 27, 813 (1998).

S. D. Setzler, K. T. Stevens, L. E. Halliburton, M. Yan, N. P. Zaitseva, and J. J. DeYoreo, "Hydrogen atoms in KH2PO4 crystals," Physical Review B 57, 2643 (1998).

S. D. Setzler, M. Moldovan, Z. Yu, T. H. Myers, N. C. Giles, and L. E. Halliburton, "Observation of singly ionized selenium vacancies in ZnSe grown by molecular beam epitaxy," Applied Physics Letters 70, 2274 (1997).

M. Moldovan, S. D. Setzler, T. H. Myers, L. E. Halliburton, and N. C. Giles, "Compensating defects in heavily nitrogen-doped zinc selenide: A photoluminescence study," Applied Physics Letters 70, 1724 (1997).

M. Moldovan, S. D. Setzler, Z. Yu, T. H. Myers, L. E. Halliburton, and N. C. Giles, "Photoluminescence of nitrogen-doped zinc selenide epilayers," Journal of Electronic Materials 26, 732 (1997).

S. D. Setzler, L. E. Halliburton, N. C. Giles, P. G. Schunemann, and T. M. Pollack, "Electron paramagnetic resonance and photoluminescence studies of point defects in zinc germanium phosphide (ZnGeP2)," Materials Research Society Symposium Proceedings 450, 327 (1997).

M. Moldovan, S. D. Setzler, Z. Yu, T. H. Myers, L. E. Halliburton, and N. C. Giles, "Photoluminescence and electron paramagnetic resonance of nitrogen-doped zinc selenide epilayers," Materials Research Society Symposium Proceedings 442, 555 (1997).

K. T. Stevens, N. C. Giles, and L. E. Halliburton, "Photoluminescence and micro-Raman studies of as-grown and high-temperature-annealed KTiOPO4," Applied Physics Letters 68, 897 (1996).

L. E. Halliburton, N. C. Giles, P. G. Schunemann, and T. M. Pollak, "Electron paramagnetic resonance of Ni+ impurities in AgGaSe2," Journal of Applied Physics 79, 556 (1996).

M. P. Scripsick, D. N. LoIacono, J. Rottenberg, S. H. Goellner, L. E. Halliburton, and F. K. Hopkins, "Defects responsible for gray tracks in flux-grown KTiOPO4," Applied Physics Letters 66, 3428 (1995).

L. E. Halliburton, G. J. Edwards, M. P. Scripsick, M. H. Rakowsky, P. G. Schunemann, and T. M. Pollak, "Electron-nuclear double resonance of the zinc vacancy in ZnGeP2," Applied Physics Letters 66, 2670 (1995).

N. C. Giles, L. E. Halliburton, P. G. Schunemann, and T. M. Pollak, "Photoinduced electron paramagnetic resonance of the phosphorus vacancy in ZnGeP2," Applied Physics Letters 66, 1758 (1995).

L. E. Halliburton, G. J. Edwards, P. G. Schunemann, and T. M. Pollak, "Observation of electron-paramagnetic-resonance spectra in as-grown CdGeAs2," Journal of Applied Physics 77, 435 (1995).