Surface plasmon polariton (SPP) excitation at a gold-vacuum interface via 800 nm light pulses mediated by a periodic
array of gold ridges is probed at high lateral resolution by means of photoemission electron microscopy (PEEM). We
directly monitor and quantify the coupling properties as a function of the number of grating ridges and compare the
PEEM results with analytic calculations. An increase in the coupling efficiency of ≈ 3 is observed when increasing the
number of ridges from 1 to 6. We observe, however, that a further addition of ridges is rather ineffective. This saturation
behavior is assigned to the grazing incidence excitation geometry intrinsic to a conventional PEEM scheme and the
limited propagation distance of the SPP modes at the gold-vacuum interface at the used wavelength.
Systematic investigations of luminescence lifetimes of organic phenylene nanofibers are presented as a function of intrinsic parameters such as morphology or bleaching factor as well as extrinsic parameters such as substrate material, coating or excitation intensity. By varying either one of these parameters, the decay times of the electronic excitation can be varied. This should have a strong influence on the efficiency of nanolasing, which is observed by increasing the excitation intensity of a femtosecond pump laser. Lasing action starts at pump fluences as low as a few μJ/cm2 per pulse. In ensemble measurements, the number of lasing modes depends strongly on the density of contributing nanofibers. In spatially resolved measurements, the nonlinear optical response of individual nanofibers is investigated. This enables us to make a correlation between the morphological features of the nanofibers, as deduced from atomic-force microscopy, and their lasing properties.