We describe how singlet oxygen fluorescence can be observed and quantified using an ID230 detector together with an ID900 Time Controller.
The dosimetry of singlet-oxygen, through its luminescence at 1270 nm, is a challenging task due to the low efficiency of the process and consequently extremely low light emission levels. Photomultipliers have traditionally been used for this purpose but these devices have low efficiencies, high noise and are sensitive to ambient light and are not fiber-coupled, precluding their use in some scenarios.
More recently, super-conducting nanowire detectors have achieved sufficiently low noise to directly detect singlet-oxygen luminescence, but have the disadvantage of requiring advanced cryogenic cooling and having a small active area of approximately 100 μm2 (single-mode fibre).
On the other hand, the ID230 offers the same low noise, efficiencies of up to 30%, does not require cryogenic cooling and works with multimode fibers, resulting in a collection area of 10’000 μm, and therefore a 100x stronger observed signal.