Figure 1
From: Diffraction Interference Induced Superfocusing in Nonlinear Talbot Effect
Theoretical model.
(a) A circular aperture. (b) A donut-like aperture with an α-phase inside circle and a β-phase outside ring. (c) The “object” in nonlinear Talbot effect, i.e., the generated SH waves with binary phases (α = 0 and β = π) at the output surface of a squarely poled LiTaO3 crystal. (d) Diffracted intensity distributions with apertures of (a) and (b) in the Fresnel near field. Obviously, the aperture (b) gives a smaller Airy disk than the aperture (a). With use of the aperture (c), periodic superfocused spots are expected to be observed in the Fresnel near field.
