Non-paraxial geometric focusing with linear arrays of point emitters

The novel concept of non-paraxial geometric focusing is theoretically discussed and numerically analyzed for linear arrays of point emitters at the scale of integrated photonics. This pure geometric method does not require micro-lenses or diffractive elements and produces a focus volume with a rotation symmetric Lorentzian distribution of the power spectrum on the focal plane. Non-paraxial geometric focusing gives new insight on interference and diffraction and provides promising specific features for technological applications, such as the "dark focus," potentially suitable for optical binary switching.