Fig. 2: Device characterization.
From: Integrated photonic metasystem for image classifications at telecommunication wavelength
a The schematic illustration of the confocal set-up. The infrared laser beam is firstly expanded by the beam expander (BE). The reflection from the programmed micromirror device (DMD) carries the input pattern. The reflected image is then focused on the input grating couplers arrays. The output signal is coupled to a single-mode fiber (SMF) through a grating coupler. An IR camera is used to monitor the light coupling on and off the chip through a beam splitter (BS). The bottom insets are the input images for the letter ‘X’, ‘Y’, and ‘Z’. b The device under test (DUT) includes arrays of metasystems fabricated on a silicon-on-insulator (SOI) substrate. c SEM images show the nanostructure of the input grating coupler array and (d) metasurface structures.
