Reconstruction of electromagnetic field states by a probe qubit

Abstract: We propose a method to measure the quantum state of a single mode of the electromagneticfield. The method is based on the interaction of the field with a probe qubit. The qubitpolarizations along coordinate axes are functions of the interaction time and from theirFourier transform we can in general fully reconstruct pure states of the field and obtainpartial information in the case of mixed states. The method is illustrated by severalexamples, including the superposition of Fock states, coherent states, and exotic states generated by the dynamical Casimir effect.