It is well known that optical twin-beam states (TWB) generated by spontaneous parametric down-conversion (PDC) exhibit spatial and spectral correlations, which can appear in single-shot images obtained by using an imaging spectrometer to resolve emission angles and wavelengths simultaneously. By analyzing series of single-shot images recorded by an EMCCD camera at different powers of the pump beam, we studied the evolution of several quantities characterizing the generated TWB. In particular, we demonstrated that correlation widths in spectrum and space increase monotonically at low pump powers and then start decreasing at higher powers due to the onset of pump depletion. In a complementary way, the Fedorov ratio decreases and then increases again. At the same time, the number of modes evaluated from photon statistics follows a complementary behavior to correlation widths that can be interpreted in terms of the evolution of the number of Schmidt modes in the field.

Date Published: 7 May 2015
PDF: 7 pages
Proc. SPIE 9505, Quantum Optics and Quantum Information Transfer and Processing 2015, 950508 (7 May 2015); doi: 10.1117/12.2178469

Published in SPIE Proceedings Vol. 9505:
Quantum Optics and Quantum Information Transfer and Processing 2015
Konrad Banaszek; Christine Silberhorn, Editor(s)