Abstract

Biological samples when subjected to cryogenic temperatures display an inherent disorder which gives these samples glass-like properties. Thus the high resolution optical techniques such as fluorescence line narrowing (FLN) [1] and hole burning [2] which have been developed to probe into the inhomogeneously broadened absorption spectra of impurity molecules in glasses are increasingly being used to investigate biological samples. FLN, for example, has been used to study DNA-carcinogen complexes at physiological damage levels [3,4] and protein-chromophore interactions [5]. Hole burning has been used extensively to study electron and energy transfer processes in photosynthetic systems [6,7]. Because the band widths obtained by these techniques are so narrow compared with room temperature absorption widths, Stark shifts and broadening and pressure effects on the spectra can be accurately measured.

© 1998 Optical Society of America