Dr. Wm. Randall Babbitt

Phone: 406.994.6156




B.S. in Physics, 1982 Stanford University

Ph.D. in Physics, 1987 Harvard University

Research Interests
Professor Babbitt’s main research interest is developing applications of spatial-spectral holography. Spatial-spectral holography combines the spatial storage and processing attributes of persistent spectral holeburning. Spatial-spectral holographic (SSH) phenomenon encompasses optical coherent transients, photon echoes, and time-domain spectral hologram analogous to the manner in which angled beams are recorded in spatial holograms. A SSH material is basically a fully programmable spectral filter with ultra-high spectral resolution and broad processing bandwidth whose impulse response is dictated be the programming pulses and their temporal shapes and their relative delay and directional. An appropriately programmed material processes incoming broadband optical beams by multiplying their Fourier decomposition be the material’s programmed frequency response, resulting in a processed output temporal waveform. SSH materials thus offer an unmatched ability to store, process, and route complex broadband optical signals with precise phase and delay control.


Dr. Krishna Rupavatharam

Senior Research Scientist
Phone: 406.994.7675






M.Sc Physics, SSS Institute of Higher Learning, Prashanti Nilayam, India
Ph.D. Physics, Indian Institute of Science, Bangalore India
Research Interests
Krishna's current research is geared towards developing applications of S2 technology. He has worked on developing a microwave spectrum analyzer for capturing and analyzing large bandwidth RF signals. Krishna's past research involved modeling and high level simulation of the S2CHIP as well as the design and implementation. He is also an adjunct faculty at Lund Institute of Technology and engages in research on quantum information processing involving rare-earth doped crystals. Krishna joined the Spectrum Lab in the Fall of 1999 as a research scientist.

Krishna's doctoral thesis dealt with Optical Phase Conjugation and Phase Conjugate Interferometry. The research involved the development of phase conjugate holographic devices using both polymers and photorefractive crystals, transient phase conjugation in polymers, high sensitivity phase conjugate and holographic real-time interferometers.

In 1997, he joined Prof. Kroll's group in Lund Institute of Technology, Lund, Sweden, where he worked on time domain optical data storage and quantum optics of phase memory systems. The research included diverse topics such as single photon self-interference realization, time domain analog of Fresnel to Fraunhofer diffraction transition, bit-selective erasure of photon echo based memories and fiber-based photon echo amplifiers.



Chris Ebbers

Senior Research Engineer

Phone: 406.994.7550






Dr. Charles Thiel

Senior Research Scientist
Phone: 406.994.5239

Diane Wesen Harn



Phone: 406.994.7596

Phone: 406.994.6279


Diane joined the Spectrum Lab in June of 2014.