Ultrafast Excitation and Deexcitation of Local Vibrational Modes in a Solid Matrix: The Si-H Bond in Amorphous Silicon

Recent advances in femtosecond laser technology have made it possible to answer experimentally the question of how long a vibrational excitation can remain localized on a single bond in a solid matrix. From these measurements, we can infer quantitative information on the local atomic arrangement and the coupling of a specific bond to the matrix. If energy can remain localized for long periods of time, several new applications may emerge, such as laser-assisted growth. Although related work is already being performed on isolated molecules, when the bonds are imbedded in a solid matrix, many new channels for energy decay open up. As a result, there is to our knowledge no reliable theoretical work on the deexcitation of localized vibrational modes in a solid matrix.