Sprecher
Beschreibung
We present recent findings from neutron diffraction measurements on hyperbranched polymer (HBP) dispersed nanocomposite gratings, revealing the highest scattering length density (SLD) modulation amplitudes to date. Optimized for light diffraction, these materials exhibit ultrahigh refractive index modulation (∼ 3×10^(-2)). The first test for slow neutron diffraction was conducted at the SANS-I instrument in Paul Scherrer Institute, using a grating with the optimal composition for light diffraction as described in Ref. [1]. Despite the low diffraction efficiency values, due to the very small grating thickness (< 10 µm) and the relatively short neutron wavelength used (≃ 2 nm), a five-coupled-waves analysis revealed SLD modulation amplitudes surpassing our recently reported records with nanodiamond-based gratings in Ref. [2]. Higher diffraction efficiencies at longer neutron wavelengths, such as those available at the ILL's PF2 instrument, are promising. The task of fabricating two- to three-times thicker gratings in the future becomes demanding. Our findings contribute to the development of reliable and efficient optical elements for slow neutron experiments.
[1] A. Narita et al., Opt. Mater. Express, 11(3), 614-628, 2021.
[2] E. Hadden et al., Appl. Phys. Lett., 124(7), 071901, 2024.
