GEC Student Excellence Award Finalist Presentation - Electric-field-vector-profile measurement in gases based on electric-field-induced second-harmonic generation

Electric-field measurement based on the electric-field-induced second-harmonic generation (E-FISHG) method has attracted attention because of its noninvasive field measurement in plasmas and gases [1]. In the E-FISHG method, the E-FISHG signal changes depending on the polarization of the probe laser beam. It is expected that this characteristic can be used to measure the direction of the electric field. In this paper, we investigate the optimal laser energy for the measurement and measure an electric-field-vector profile. We use an optical geometry such that it is sensitive only to the electric field component parallel to the polarization of the laser beam and acquire an E-FISHG signal by rotating the polarization. The dependence of the E-FISHG signal on the polarization angle corresponds to the simulated result below the filamentation threshold energy. We have proposed a method to restore a one-dimensional electric-field-profile from a sequence of E-FISHG signals along the probing laser path [2]. We measure an electric field vector profile under the filamentation threshold energy by this method. We successfully restore the one-dimensional electric-field-vector profile from the E-FISHG signal along the laser path.