We show that a configuration of four birefringent crystals and wave-plates can emulate almost any arbitrary unital channel for polarization qubits encoded in single photons, where the channel settings are controlled by the wave-plate angles. The scheme is applied to a single spatial mode and its operation is independent of the wavelength and the fine temporal properties of the input light. We implemented the scheme and demonstrated its operation by applying a dephasing environment to classical and quantum single-photon states with different temporal properties. The applied process was characterized by a quantum process tomography procedure, and a high fidelity to the theory was observed.
Bibliographical noteFunding Information:
Israel Science Foundation through the Eshkol fellowship (546/10, 793/13); Ministry of Science, Technology and Space.
© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement