Fig. 1.

(a) Conventional unidirectional focusing scheme with single lens. (b) Conventional isotropic focusing scheme with two aligned lenses. The aperture angle (contributing k-vector components) for the focused light beam is doubled in the isotropic focusing scheme. (c-f) Conventional and OPC-assisted isotropic focusing in two circumstances – (c and d) with lateral misalignment (e and f) and through inhomogeneous media. The conventional system fails to maintain isotropic focusing for both cases, while the OPC-assisted system adaptively corrects the aberrations.