Extended Data Fig. 2: Metalens-based TPL system.
From: 3D nanolithography with metalens arrays and spatially adaptive illumination
a,b, Schematic of the metalens-based TPL system and a zoomed-in view showing the printing of gradient structures with patterned laser beam. HWP1, HWP2: half-wave plates; PBS1, PBS2: polarization beam splitters; QWP1, QWP2: quarter-wave plates; L1, L2, L3: lenses; BE: beam expander; OBJ: objective lens; BS: beam splitter. c, Photo of the optical set-up.
