Role of Ultrafast Shaped Pulses in Classical and Quantum Optics

摘要

This report presents the results of studies of the generation and characterization of Electron Paramagnetic Resonance (EPR) and the entangled bi- photon state using optical parametric downconversion (PDC) with ultrashort- duration pump pulses. The authors have advanced a method of generating photon pairs that are highly entangled in their continuous space-time degree of freedom and have developed theoretical tools for quantifying the degree of entanglement for this and other continuum-variable systems. In addition, they have shown for the first time the violation of a Bell-type inequality for the EPR state generated in parametric downconversion. The studies also show, theoretically, that it is possible to design sources such that the photon entanglement causes complete nonlocal cancellation of dispersion of arbitrary order, and demonstrate the increase in visibility using properly mode-matched photons. In addition, the authors have analyzed the effects of nonmeasured degrees of freedom of photons generated by PDC on the basic elements of linear optical quantum logic gates, such as a prototypical Bell-state analyzer. The results have implications for novel methods of quantum communications using both entangled and unentangled modes and photons. A list of 13 related manuscripts is included.