Dr. Tom Christensen
Optical Properties of Rough Surfaces.
We are examining the properties of rough surfaces. Microscopic roughness of surface is being examined using beam profiling techniques on laser light reflected from the surface and spectroscopic, multiple angle of incidence ellipsometry. Macroscopically rough paper surfaces are also being examined to determine effects of roughness on ellipsometry and light scattering techniques. Results are compared with Scanning Electron Microscope data and stylus profilometer data.
Relation of Film structure to magnetic properties:
Investigations of layered systems containing magnetic films (Fe,
Permalloy or Co for example) show remarkable magnetic properties. The
effects appear to depend on the manner in which the superlattice
layers are produced. This suggests that material properties such as
interfacial roughness or film density may be important. We produce
thin film layered structures and devices of various materials using
Molecular Beam Epitaxy, sputter deposition and electron-beam
evaporation and examine the effects of material properties on the
magnetic properties. Materials are characterized using ellipsometry,
scanning electron microscopy (SEM), Auger electron spectroscopy
(AES), profilometry, magnetoresistance, magneto-optic Kerr effect,
and Brillouin light scattering (BLS) measurements.
Morphology of film growth:
As films develop from scattered atoms on a substrate to continuous
films, their structure and properties can change. This is done by
growing films for different deposition times and studying each sample
with several techniques. We use ellipsometry, Auger electron
spectroscopy, and scanning electron microscopy to examine each
sample.
Non-linear optical properties of polymer films
Workinig with the U.S. Air Force Academy Laser and Optics Research
Center, we have been examining the non-linear properties of inorganic
and polyer materials. Experiments have involved two-beam coupling and
four-wave mixiing experiments.