Photonic-Based Time-Resolved Multipulse Oxygen Sensor

Oxygen is one of Earth's vital elements, and its accurate measurement is crucial in numerous scientific and medical applications. Photonic-based sensors have recently become the subject of great attention for oxygen measurements due to their highly promising characteristics. These include the lack of requirement for repetitive calibrations and replacement of parts, being contactless, their accuracy, and fast response, and the potential to fabricate such sensors in small sizes. Here, we develop a dissolved-oxygen sensor by integrating time-resolved photoluminescence spectroscopy employing an FPGA-controlled multi-pulse LED source and amplified fast photodetector mounted on a PCB, light-emitting platinum porphine complex embedded polystyrene molecular oxygen-sensing probe, and a two-site Stern-Volmer function for the sensing and calibration. The PCB excites the molecular probe with multiple 50 ns blue light pulses, and the emission lifetime is extracted using an exponential function based on the Levenberg-Marquardt nonlinear fitting. Complete characterization of the sensor, including its sensitivity, repeatability, stability, and response time, in addition to the temperature and altitude compensation, is implemented to achieve excellent dissolved-oxygen sensing functionality.