Fig. 2: Phase sensitivity of Diff-CUP.

a Spatiotemporal interferograms of a 2.6-ns EMP in the LN crystal captured by the streak camera and simulated by the electric field and phase distribution model, and the corresponding temporal phase averaging over the x direction. Horizontal scale bars, 300 µm. Vertical scale bars, 500 ps. b Experimental interferogram of a 150-ps propagating EMP and the corresponding temporal correlation of Fringes 1–4. D is the spatial distance between Fringes 1 and 4. The inset at the bottom right shows the approach to calculate the propagation time, T, of the EMP through the LN (top right). Horizontal scale bar, 300 µm. Vertical scale bar, 50 ps. c Quantification of phase-sensitivity of uncoded Diff-CUP by inducing EMPs with different amplitudes in the LN crystal. Each curve represents a reconstructed pulse shape with a different amplitude, where the corresponding phase change is shown above the curve. Black arrows denote the pulse width of the EMP. d Spatiotemporal interferograms of a weak EMP propagating in the LN crystal. Left, unprocessed interferogram, i.e., control group. Middle, interferogram processed with the temporal correlation (TC) and template matching (TM) methods. Right, interferogram processed with the TC, TM, and differential approach. Black dashed lines denote the regions of the EMP. Horizontal scale bars, 300 µm. Vertical scale bars, 20 ps. e Reconstruction of the pulse shape of the weak EMP using the three interferograms in (d).