Figure 4.

Behavior of the Alvarez lens in response to x displacement. (a,d,g) represent the phase profiles of one Alvarez element for displacements of 10p, 20p, 80p respectively, (b,e,h) represent their inverses at displacements of −10p, −20p, −80p respectively, and (c,f,i) are the sums of the displaced phase profiles. The phase profiles are displaced in units of the metasurface lattice periodicity p = 443 nm, with (a–c) representing a 4.43 μm displacement, (d–f) representing 8.86 μm displacement, and (g–i) representing a 35.4 μm displacement. (j) Plot of focal length dependence on displacement based on equation 4. Larger displacements result in a more rapidly varying phase profile, corresponding to a lens with a smaller focal length. The colored dots indicate the focal lengths of lenses shown in (c,f,i). Parameters used are the same as for the fabricated device, L = 150 μm, A = 1.17 × 10⁷m⁻².