EO sampling methods for real-time THz imaging

We have developed a method of real-time terahertz (THz) imaging in which image deformation due to nonuniformity of residual birefringence in the electro-optic (EO) sampling crystal is corrected. Real-time THz imaging using intense THz pulses and two-dimensional EO sampling can suffer from birefringence nonuniformity of the EO crystal since the birefringence is explicitly used for the linear detection of the THz field. In the proposed method, the distribution of the residual birefringence of the EO crystal is measured and used for image correction. Deformation-free images of the spatial profile of a focused THz pulse were obtained.