Quantum interferometric lithography with pair-coherent states

Abstract

We investigate a quantum interferometric lithography system using pair-coherent states as resources to excite an $N$-photon recording medium. The interference pattern is found to have half the period of the classical light interference pattern limited by the Rayleigh criterion. The fringe visibility is nearly unity in the low-flux region and decreases with increasing values of the average photon number. We show that as $N$ increases, the high-flux limit visibility increases and the bright-fringe width decreases; however, the fringe period and spacing remain the same. Compared with the results using two-mode squeezed vacuum states, although our results have the same high-flux limit visibility, we can get higher contrast and narrower bright-fringe patterns under the same conditions of light flux and lithography material. Our approach sheds light on quantum lithography with nonclassical light and reveals how pair-coherent states can be superior to two-mode squeezed vacuum states.