Fig. 1. Optical pulse shaping using cascaded metasurfaces.

(A) Schematic diagram of a Fourier transform pulse shaping setup, consisting of a pair of diffraction gratings (G₁ and G₂), a pair of parabolic mirrors (PM₁ and PM₂), and a cascaded sequence of metasurfaces matrices S_i (i = 1, 2, … n). Each matrix S_i consists of m different metasurfaces (M_i,j=1 to M_i,j=m). An input optical pulse upon propagation through this setup is transformed into a shape-modified output pulse of tailored temporal characteristics. (B) Pulse shaping at the Fourier plane of the setup. A given metasurface M_i,j is discretized to N individual sectors to treat in parallel the broad range of frequencies (ω_k for k = 1 to N), imparting a complex transfer function t_i,ke^iφ_i,k for each ω_k. The spectral components of the input pulse are treated in parallel through a location specific effective masking function of complex amplitude t_ke^iφ_k, where $t_k={\prod }_{i=1}^n{t}_{i,k}$ and ${\phi }_k={\sum }_{i=1}^n{\phi }_{i,k}$.