Remote measurement of electric fields based on electric-field-induced second-harmonic generation using a nanosecond laser at a distance of 10 meters

We demonstrated remote electric field measurements up to 10 m using electric-field-induced second harmonic generation (E-FISH) with a nanosecond pulse laser. The performance was evaluated at distances of 2 m and 5 m by varying beam diameter, pulse energy, and focal length. SHG intensity followed the theoretical electric-field dependence, and linear polarization was maintained, enabling field direction measurement. The SHG signal showed a Lorentzian distribution along the optical axis under all tested conditions, allowing spatial profiling. Electric field reconstruction was also performed at 5 m and 10 m based on SHG signal distributions. At 10 m, the peak error in the inferred electric field was only 0.7%, confirming the method's high accuracy. These results validate the practicality of nanosecond-laser-based E-FISH for long-range, direction-sensitive electric field diagnostics.