Fig. 4. 3D direct laser writing of a vectorial hologram for the lensless reconstruction of 3D vectorial field–carrying and vectorial field–multiplexing holographic images.

(A) Optical setup for the lensless reconstruction of a 3D vectorial holographic image, wherein a pair of laser-printed phase patterns were used to modulate two orthogonal circular polarization for the generation of the MANN-derived 2D vector fields, which are further directed to a digital phase hologram. The insets present the optical images of the printed high-resolution phase patterns, each of which is with a size of 2 mm by 2 mm. The red arrows label out the laser beam propagation directions. BS, beam splitter; LP, linear polarizer; HWP, half-wave plate; QWP, quarter-wave plate; PBS, polarizing beam splitter. (B) Experimental characterization of the lensless reconstruction of a 3D vectorial holographic image. The insets show the two-photon fluorescence images of the three orthogonal components of a randomly selected pixel in the reconstructed vectorial holographic image. Scale bar, 1 μm (inset). (C) Experimental verification of the divisibility property of a vectorial hologram based on different sections of a laser-printed vectorial hologram. The insets show the optical images of the laser-printed sectional vectorial holograms and their experimentally reconstructed holographic images, respectively. (D) Schematic illustration of the 3D vectorial mapping of eight vector-field distributions in a designed spiral shape as a function of azimuthal angle α. (E) Experimentally reconstructed 3D vectorial field–multiplexed holographic image designed in (D) on a CCD, wherein eight enlarged pixels with pseudocolors were used to highlight the different 3D vectorial fields (insets). Scale bar, 1 μm (inset).