Laser multiphoton processes in thin films: Non-linear photochemistry of organosilane polymers

Irradiation of organosilane polymers in the ultraviolet leads to photodegradation of the chain via a bond scission process. Here photodegradation by visible laser multi-quantum excitation is reported. The process is characterized by a sharp threshold at power densities of approximately 2.5 GW/cm2. The photochemistry of the system beyond this power density proceeds non-linearly leading to vaporization of the absorbing film and 100% bleaching of the ultraviolet absorption bands. Utilization of laser wavelengths whose two-photon energies are insufficient to access the ultraviolet system, produced no measurable photodecomposition. © 1985.