Abstract

The response of complex biomolecules to sequences of ultrafast optical pulses provides multidimensional snapshots of their structure and electronic and vibrational dynamics. Twodimensional correlation plots of the signals show characteristic cross-peak patterns which carry information about structures, equilibrium binding fluctuations and relaxation processes. The lineshapes provide information on conformational and solvent induced fluctuations. The fundamental concepts underlying the design and interpretation of these coherent nonlinear experiments will be surveyed. New pulse sequences may be constructed for probing specific coherences, building upon the analogy with multidimensional NMR. Computational techniques for simulating the necessary multipoint response functions will be presented. Applications will be made to ideal secondary structural motifs of peptides, protein folding dynamics, Amyloid fibrils and hydrogen bonding. Resolution may be enhanced by applying novel polarization configurations of the optical fields which also provide chirality-specific information. The use of pulse shaping coherent control strategies and sensitivity analysis to simplify complex spectra and retrieve and enhance desired features will be demonstrated. Future extensions to the attosecond regime using x ray pulses will be discussed.

© 2007 Optical Society of America