Highly sensitive oxygen gas sensor using surface plasmon with a common path homodyne interferometer

We constructed an oxygen gas sensing system in which the concentration of the oxygen gas was determined by measuring the phase change related to the surface plasmon with a common path homodyne interferometer. Hemoglobin was used as a sensing material for the oxygen sensor system. It was experimentally found that the detection limit of oxygen gas was as low as 10 ppm in oxygen concentration and the average time for the reaction between oxygen gas and hemoglobin was less than 0.42 s at room temperature.