Supercontinuum assisted trapped electron accumulation in titanium oxide gel by femtosecond laser pulses

Long-lived trapped electrons are generated in titanium oxide gels in a convergent part of a loosely focused beam from a millijoule, femtosecond Ti:Sapphire laser. The appearance of trapped electrons is accompanied by the generation of the white supercontinuum. Considering the relevant physical mechanisms of trapped electron accumulation, we show that two-photon interband transitions with participation of photons at the fundamental frequency and from the blue part of the supercontinuum explain the experimental findings.