Harmonic lens with an annular aperture

We have considered the design of a compact imaging lens based on a reflective circular harmonic lens. The performance of such a lens has been numerically simulated in the ZEMAX program. A point spread function has been calculated. A number of formulae describing the relationship between the key parameters of the lens have been obtained. We have shown that in this case it is possible to design a compact imaging lens whose length is by an order of magnitude smaller than its focal length.