Near infrared spectral hole burning in Si-naphthalocyanine-doped solids: enhancement of the hole-burning efficiency by co-doping with C70 fullerene

In search for efficient near infra-red systems exhibiting broadband significant persistent spectral hole-burning properties for coherent femtosecond pulse-shaping purposes, we have recently demonstrated the potentiality of C70 fullerene to act as an optical enhancer of the hole-burning properties of Si-naphthalocyanine (SiNPc)-doped PVB films in two-colour hole-burning experiments. We hereby report on an increase of the one-colour hole-burning efficiency of SiNPc when C70 is present. We present some spectroscopic evidence that the energy initially absorbed by SiNPc molecules excited at 792 nm is transferred to C70 fullerene molecules, allowing them to play a role as hole-burning activators.