Fig. 3: Experimental demonstration of a spatial/polarization mode multiplexer.
From: Complete vectorial optical mode converter using multi-layer metasurface
a Profiles of the geometric meta-atom parameters Dα, Dβ, and \({\gamma }^{{\prime} }\). b Microscope images of the fabricated folded MS device at the MS and output side (bottom) and at the input side (top). c Scanning electron microscope (SEM) image of the fabricated MS before depositing the polyimide layer. d Measurement setup. VOA variable optical attenuator, PC polarization controller, Obj. objective lens, Pol. polarizer, FC fiber collimator, HWP half-wave plate, BS beam splitter, NIR near infrared. The right inset shows a photograph of the mode multiplexer chip with the input single-mode fiber (SMF) and the objective lens. e Measured complex field profiles at the output plane in X-and Y-polarization. f Measured mode-matching matrix S.
