Photon-sieve lithography.

We present the first lithography results that use high-numerical-aperture photon sieves as focusing elements in a scanning-optical-beam-lithography system [J. Vac. Sci. Technol. B 21, 2810 (2003)]. Photon sieves are novel optical elements that offer the advantages of higher resolution and improved image contrast compared with traditional diffractive optics such as zone plates [Nature 414, 184 (2001)]. We fabricated the highest-numerical-aperture photon sieves reported to date and experimentally verified their focusing characteristics. We propose two new designs of the photon sieve that have the potential to significantly increase focusing efficiency.