(37) In CARS excitation, the pump and Stokes fields coherently drive all resonant oscillators in the excitation volume
at [[omega].sub.p] [[omega].sub.s], generating a third-order polarization at the anti-Stokes frequency.
A requisite of paramount importance for single fluorescent molecule detection is the reduction of the excitation volume
of the molecule in order to discriminate the signal emitted by a single molecule among the signal arising from surrounding molecules, which acts as an interfering background .
All photosensitization studies were successful in producing singlet oxygen and TPE was found to be efficient in producing singlet oxygen in a small excitation volume
as compared to OPE.
Auger electron emission occurs within the same excitation volume
; however, inelastic scattering in the solid prevents subsurface Auger electrons from contributing to the peaks in the Auger spectrum.