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Hans Hallen

Professor

Riddick Hall 258F

919-515-6314

Bio

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.

Research Description

Professor Hallen 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.

Selected 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)
A. Willitsford, C. Chadwick, S. Kurtz, C. Philbrick, H. Hallen
J of Phyical Chemistry A, 120 (4), (2016), p.503-506

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

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

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

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

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

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