Near-field two-photon nanolithography using an apertureless optical probe

Near-field two-photon optical lithography is demonstrated by using ;120 fs laser pulses at 790 nm in an apertureless near-field optical microscope, which produces lithographic features with ;70 nm resolution. The technique takes advantage of the field enhancement at the extremity of a metallic probe to induce nanoscale two-photon absorption and polymerization in a commercial photoresist, SU-8. Even without optimization of the resist or laser pulses, the spatial resolution of this technique is as high as l/10, nearly a factor of 2 better than techniques based on far field two-photon lithography. © 2002 American Institute of Physics. @DOI: 10.1063/1.1519329#