A Singlet Oxygen Image with 2.5 μm Resolution

Upon irradiation of a photosensitizer, singlet molecular oxygen has been detected via its a1Δg → X3Σg- phosphorescence with a microscope. Using this tool, a singlet oxygen image with 2.5 μm resolution has been constructed of a phase-separated toluene/water mixture. For the a → X transition at ∼ 7850 cm-1 (∼ 1270 nm), a lateral resolution of 2.5 μm is close to the diffraction limit of ∼1.5−2.0 μm.