Three-photon absorption measurements in hematoporphyrin IX: “Ground-breaking opportunities in deep photodynamic therapy”

In this Letter, we report the three-photon absorption of hematoporphyrin IX (HpD-IX) in DMSO solution pumping at 1200 nm with a 25 ps pulse laser-OPG system. The obtained three-photon absorption cross-section in HpD-IX, σ3′=1.2×10-78cm6s2ph-2, is considerably high. Because HpD-IX is one of the main constituent of Photofrin® II, the only approved photodynamic therapy drug by the Food and Drug Association, this result is expected to have an impact in deep bioimaging and photodynamic therapy using currently available photosensitisers.