771 / 2022-03-31 21:51:45

Surface potential measurement based on optical fiber electrostatic sensor

Electrostatic sensor,Surface potential,Fabry- Perot,Surface charge

Purpose/Aim

In order to better understand the mechanism and phenomenon of surface charge accumulation and decay, there is a major challenge for obtaining the information regarding the distribution of surface potential. Therefore, we have developed a novel optical fiber electrostatic sensor based on Fabry-Perot (F-P) interference principle. It exhibits some advantages like high resolution, passive detection, fast response, and excellent anti-interference ability during the test.

Experimental/Modeling methods

The self-developed optical fiber electrostatic sensor is applied to measure the surface potential on polyethylene terephthalate (PET) with different roughness. It is mainly consisted of an electromechanical transducer at the sensitive terminal, an optical fiber collimator at the fixed terminal, sensing probe and F-P cavity. The induced potential makes piezoelectric actuator generate micro deformation, which further leads to the change in length of F-P cavity. Finally, the above changes could result in the shift of the output spectrum, and the measurement of electrostatic voltage can be realized by demodulated phase of the output spectrum.

Results/discussion

The surface potential obtained by optical fiber electrostatic sensor agrees well with that of electrostatic capacitance probe (ECP). With the increase of the surface roughness, the surface charge accumulation and decay on the surface of dielectric material are inhibited.

Conclusions

Surface roughness of the sample could have restraining effect in the surface charge decay characteristic. Optical electrostatic sensor based on F-P interference principle with high resolution is expecting to become a feasible approach for obtaining the accumulation and decay status of the surface charge. In the future, a scanning set-up based on optical fiber of electrostatic measurement is promising to demonstrate the surface charge distribution status in a passive measurement.