Collective method for fast simulations of large photon sieves

The photon sieve (PS) is a diffractive optical lens that consists of many individual pinholes, in some cases, up to 10⁹. This large number poses a challenge if the field in the focal plane is calculated by a summation of individual field contributions. Here, we present a collective model. Using the properties of the spiral Fourier transform and dividing the PS into pinhole groups, the computational effort is significantly reduced. With this approach, a FalconSAT-7-type PS can be simulated within minutes-in special cases, even less than a minute-on a conventional PC.