Development of an electric field sensor based on second harmonic generation with electro-optic materials

A novel approach of measuring an impulse electric field is proposed by combining a nonlinear optical-frequency conversion technique, such as the second-harmonic generation (SHG), with the electro-optic effect. The technique involves measurement of an electric field based on the SHG output intensity. In the present work, a continuous-wave diode laser is used with nonlinear, electro-optic crystals, such as MgO:LiNbO3 (MgO:LN) and KTiOPO4 (KTP), and the feasibility of the SHG technique for impulse electric field measurements is studied. The experimental measurements combined with theoretical estimates show that even though the temperature control is a critical requirement, the SHG technique can be effectively used for electric field measurements with a wide dynamic range of the order of a few kV/cm. It was also possible to shift the electric field measurement range by offsetting the phase matching condition for SHG.