Speaker:
Dr. Aleks Rebane, Department of Physics, Montana State University

Title:
"Tetrapyrroles: from quantum interference to cancer therapy"

Abstract:
Tetrapyrroles are organic molecules that are used for an amazing diversity of purposes ranging from dying fabrics and CD-R disks to medicine. One reason for such enormous versatility is because of strong visible absorption due to atomic-like optical transitions, which are only weakly coupled to vibrational motion. Tetrapyrroles are also inherently compatible with living organisms because of their close structural resemblance to chlorophyll.

In our group we have been studying optical and photochemical properties of porphyrins, chlorines and phthalocyanines, many of which are specially synthesized novel compounds. We have found that tetrapyrroles, which were earlier considered rather marginal nonlinear absorbers, may have very strong two photon absorption in near-infrared range of wavelengths. We also found quantum interference between alternative multi photon excitation pathways, which may play a role in the two-photon enhancement effect. These findings may facilitate new applications in areas that include quantum optics, photodynamic therapy of cancer and neuroscience.

Host:
Charles Kankelbor