Time-resolved Detection of Singlet Oxygen in a Transmission Microscope¶

The time-resolved absorption spectrum of singlet oxygen [O2(a1 delta g)-->O2(b1 sigma g+)] has been recorded in the region approximately 5100-5300 cm-1 from air-saturated polystyrene samples using a microscope attached to a step-scan Fourier transform IR spectrometer. Singlet oxygen signals were observed with a time resolution of approximately 160 ns from sample volumes of approximately 20 nL using moderate data-acquisition times. These data indicate that it is reasonable and worthwhile to consider the further development of a transmission microscope as a viable tool to create singlet oxygen images of inhomogeneous samples including samples of biological importance.