Fig. 2: Size-selective image processor using a nonlocal MDM film.

a The transmission principle involves light incidence at an angle θ_i into the MDM film, consisting of Ag and MgF₂ layers with phase accumulation δ. Simulation of electric fields at various incidence wavevectors at a 650 nm wavelength showcases that the nonlocal effect is observable only when the phase is matched (NA = 0.5), leading to maximum transmission, while conversely, transmission is nearly zero for NA of 0 and 0.9. b Simulated color-coded transmission coefficient t_pp(λ, k_r), showcases a second-order resonance within the visible light for p polarization. The selected representative wavelengths include blue (λ = 466 nm), green (λ = 532 nm), and red (λ = 650 nm) light, indicated by the corresponding-colored dashed lines. c The designed OTFs demonstrate Gaussian-type band-pass filtering at three operating wavelengths with NA ranges of 0–0.8 NA, 0.43–0.6 NA, and 0.93–0.99 NA. The solid-colored lines depict the simulated OTFs, and the dashed lines represent the corresponding ideal rectangular band-pass OTFs. The simulation results demonstrate its size-selective denoising and edge detection capabilities. d Photo of the fabricated two-inch size-selective image processor (yellow dashed box). e Wavevector-dependent transmission spectra (|t(k_r)|²) by ellipsometry at 466 nm, 532 nm, and 650 nm wavelength under p-polarized light (dashed lines), which align well with the simulation results (solid lines).