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Hans Hallen

Professor

Biography

Professor Hallen received his BS degree in Engineering Physics from Cornell University in 1984, and his MS and PhD degrees in applied physics from Cornell University in 1986 and 1991, respectively. At Cornell, he studied sub-micron-scale Josephson junctions, conducted photoemission studies of atomic ordering near interfaces of plasma-oxidized silicon, and hot-electron-induced nano-scale modifications of metal surfaces with a scanning tunneling microscope. During 1991-1993, he was with the Physical Research Laboratory, AT&T Bell Laboratories, Murray Hill, NJ where he developed the first scanning Hall probe microscope, and used it to study high temperature superconductivity and vortex propagation in small structures. He joined the North Carolina State University Physics Department in 1993.

He led the group that produced the first near-field Raman images, and identified new physics in nanoscale optical spectroscopy. He first described and measured gradientfield Raman spectroscopy, important near metallic nanostructures, which complements standard near-field Raman spectroscopy. He studied nanoscale carrier dynamics in silicon: wafers and solar cells. His results identifying electron induced motion of atoms in conductors as disparate as Au and YBCO have led to a novel view of transport of few eV electrons in metals, including grain-boundary effects. He has studied microwave propagation to test long range channel prediction algorithms for wireless communications, which enable adaptive signaling - making full use of the rapidly varying wireless signaling environment. Currently he is interested in propagation of ultrawideband pulses in shadowed environments. He has developed a nano-bioprobe for localization of optical interactions within cells, such as for studies of intracellular signal transduction pathways. He has also shown that similar probes can be used to manipulate the nucleus out of and in to cells. He has active projects in nanoscale characterization with scanning proximal probe microscopes utilizing optical, electrical, and photoemission probes. He is investigating in-plane oriented molecular deposition with nanoscale lateral resolution, scanning nano-transport microscopy, surface modification for functionality, Raman lidar techniques, and novel nanoscale material approaches for 3-D packaging of RF wafers.

Select Publications

" Resonance-enhanced raman scattering of ring-involved vibrational modes in the B-1(2u) absorption band of benzene, including the kekule vibrational modes nu(9) and nu(10)"
J of Phyical Chemistry A 120 (4). A. Willitsford, C. Chadwick, S. Kurtz, C. Philbrick, H. Hallen (2016). p.503-506

"Enhancement of single particle rare earth doped NaYF4: Yb, Er emission with a gold shell."
Nanotechnology 26 (2). L. Li, K. Green, H. Hallen, S. F. Lim, (2015).

"Resonance enhanced Raman scatter in liquid benzene at vapor-phase absorption peaks"
Opt. Express 21 (19). A. Willitsford, C. Chadwick, H. Hallen, S. Kurtz, and C. Philbrick. (2013). p.26150-26161

"Resonance enhanced Raman scatter in liquid benzene at vapor-phase absorption peaks"
Ultrafast Imaging and Spectroscopy . Hans D. Hallen ; Ryan R. Neely ; Adam H. Willitsford ; C. T. Chadwick and C. R. Philbrick. (2013). p.26150-26161

"Multistatic lidar measurements of non-spherical aerosols"
Laser Radar Technology and Applications XVIII 21 (19). Hans D. Hallen ; Brandon J. N. Long ; D. A. Hook ; Garrett E. Pangle and C. R. Philbrick. (2013). p.87310

"Electric field gradient effects in Raman spectroscopy"
Phys. Rev. Lett. 85 (19). Eric Ayars, H. D. Hallen and C. L. Jahncke. (2000).

"Electromigration in YBCO using a Metal clad Near-Field Scanning Optical Microscope Probe"
Appl. Phys. Lett. 77 (14). S. H. Huerth, M. P. Taylor, H. D. Hallen, B. H. Moeckly. (2000). p. 2127-2129.