Optical fiber hydrogen sensors/detectors
The concept:
With the increasing number of hydrogen applications the need for safety detectors increases. The current generation of hydrogen detectors is large in size and generally relies on an electrical readout at the area of measurement.
We focus on optical hydrogen detection using smart-coatings at the top of an optical fiber. Optical fibers have the advantage that they can be read at a distance and - due to their small size- many of them can be readout in parallel with a single detector.
| To detect hydrogen we us a thin film consisting of Magnesium and Titanium, which is deposited at the end of an optical fiber. At a well-defined hydrogen pressure this switchable mirror transforms into a highly absorbing state. Upto a 10-fold reduction in reflection can be observed.
The reflection of a simple diode is measured at the other end of the fiber by a photodetector. The detector switches within 20 seconds and has been tested in up to 200 cycles.
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Current research:
Presently we are investigating the role of impurities in the atmosphere on the reliability of the detector. Furthermore, we are developing a hydrogen sensor based on the same principle. Instead of a binary detection, the sensor give a variable optical output over a certain hydrogen pressure range.
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