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.