Quantum lithography: status of the field

This contribution provides an analysis of progress in the field of quantum lithography. We review the conceptual foundations of this idea and the status of research aimed at implementing this idea in the laboratory. The selection of a highly sensitive recording material that functions by means of multiphoton absorption seems crucial to the success of the proposal of quantum lithography. This review thus devotes considerable attention to these materials considerations. 1 Background and conceptual issues involving quantum lithography Quantum lithography is a technique first proposed by Boto et al. [1] that allows one to write interference fringes with a spacing N-times smaller than the classical Rayleigh limit of resolution, which is approximately λ/2. The basic idea of quantum lithography is illustrated in Fig. 1 for the case N = 2. Here a laser beam is allowed to fall onto a nonlinear mixing crystal in which parametric downconversion occurs, producing two daughter photons each at twice the wavelength of the pump laser beam. This photon pair then falls onto a 50-50 beam splitter. The output of the interferometer under these circumstances is the entangled state |2, 0〉 + |0, 2〉, where the notation is such that R. W. Boyd (B) Institute of Optics and Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA e-mail: [email protected] R. W. Boyd Department of Physics and School of Information Technology and Engineering, University of Ottawa, Ottawa, ON K1N 6N5, Canada J. P. Dowling Department of Physics and Astronomy, Hearne Institute for Theoretical Physics, Louisiana State University, Baton Rouge, Louisiana, 70803-4001, USA