Optical lithography at half the Rayleigh resolution limit by two-photon absorption resist

Recently, it has shown that Rayleigh diffraction limit (a size lambda/2) is overcome using entangled-photon pairs, where lambda is the optical wavelength. However, the intensity of the entangled-photon pairs generated from optical parametric down-conversion are so weak that it is not enough to attain the practical throughput. We propose a new method which enables to enhance the resolution over the Rayleigh limit with coherent laser light by using polarization-dependent two-photon absorption resist.