Diffraction efficiency of reflective metallic gratings operating in the THz range - Fernández M; Torquemada MC; García-Lozano G; Mercant G; Sanchez-Brea LM; Cuadrado A; Alda J; González L; Belenguer T (32nd International Symposium Of Space Terahertz Technology, Isstt 2022, 2022)