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 C-70 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 C-70 is present. We present some spectroscopic evidence that the energy initially absorbed by SiNPc molecules excited at 792 nm is transferred to C-70 fullerene molecules, allowing them to play a role as hole-burning activators. (C) 2002 Elsevier Science B.V. Ali rights reserved.