Nanophotonic Extreme Ultraviolet Polarimeter
Nanophotonic engineering has revolutionized how we manipulate the polarization of visible light. Here, we extend such control to extreme ultraviolet radiation, the spectral region of attosecond science and semiconductor lithography, where transmissive optical elements are lacking. We implement channel waveguides that restrict incident 41-nm-wavelength light to a few modes with defined spatial profiles and propagation constants. By designing the propagation-length-dependent interference of two eigenmodes, we achieve polarization-dependent forward scattering, which we exploit to create a transmissive nanophotonic analyzer that resolves the polarization axis and spectrum of extreme ultraviolet light from a single measurement. With a 0.9°-sensitivity for polarization rotations in a 1-second measurement and single-shot capability, the device opens new experimental opportunities in ultrafast magneto-optic spectroscopy and at accelerator-based light sources.