Fig. 4
Schematic and performance of frequency-dependent encrypted display. a Functional unit for frequency-dependent quaternary encoding. With electron beam impinging positions located at four inner corners and the center of the nanoantenna, which are marked with five points on the pseudo-color SEM image; corresponding color routing patterns are defined as 00, 01, 10, 11, and the erasure code for quaternary encoding. b Angular patterns of the dichromatic components in quaternary encoding, displayed in the order of 00, 01, 10, 11, and erasure code. c Image of the CRs on the PCB board and Field-Programmable Gate Array controller. d Photograph of SACNT film and gold electrodes, scale bar is 60 μm. e The SEM image of SACNT flake and Au cross nanoantenna array fabricated by electron-beam lithography, scale bar is 2 μm. f, g Two-dimensional encrypted display of capital letters “C” and “R”. In the capital letter “C”, the measured splitting patterns of dichromatic components output “01000010”, “01001001” and “01010100” corresponding to ASCII codes of capital letters “B”, “I” and “T”, respectively. In the capital letter “R”, three character strings of “01001101”, “01010010” and “01000100” are output as capital letters “M”, “R” and “D”, respectively
