Picosecond Transient Absorption of Xanthene Dyes

After one- and two-colour ps-excitation the transient absorption of rose bengal, erythrosin B and eosin Y in the spectral range from 450 to 670 nm was probed using picosecond continuum pulses generated in H$\text{}_{2}$O-D$\text{}_{2}$O mixture. Our experiments showed for all dyes a high T$\text{}_{1}$-T$\text{}_{n}$ absorption signal above 590 nm where no ground state absorption occurs. These excited triplet states can be effectively populated by a delayed second pump pulse. Their properties with special attention to reverse intersystem crossing processes from T$\text{}_{n}$ to S$\text{}_{x}$ are discussed