Microscopia de desfocalização com fótons gêmeos

Abstract

We study in this work the Defocusing microscopy for the case where the light source is a beam of twin photons. It was analysed the situation where a phase object is illuminated by photons generated by parametric down-conversion and the image is obtained by detecting the photon pairs at the defocused image plane in coincidence. By using a fourth-order correlation function in the fields at the defocused image plane we obtained an expression that allows us to calculate the detection probability of the two photons in this plane for the case of finite size lenses. This expression was calculated numerically and a comparison with a classical light source was done. A gain in the spatial resolution was observed.