Two-dimensional free space electric field imaging using electric field induced second harmonic generation

We present a new, to the best of our knowledge, approach for the measurement of the localized electric field distribution in air using electric field induced second harmonic generation combined with a microscopic imaging technique. This method only needs two snapshot second harmonic images with orthogonal polarizations to obtain the two-dimensional spatial distribution of the intensity and direction of the electric field. The distribution of a local electric field was clearly measured with a spatial resolution of 8.8 µm by using this method. The measurement of a single second harmonic image takes 5 s by using a 5 kHz repetition rate femtosecond laser.