We experimentally investigate the mode characteristics of multimode radiation fields propagating through frequency-dependent Gaussian channels. After manipulating the twin beams emitted from a conventional parametric downconversion source via spectral filtering, we study the changes in their mode characteristics, utilizing the joint normalized correlation functions. While filtering reduces the number of spectral modes, it also leads to an apparent mode mismatch, which destroys the perfect photon-number correlation between the twin beams, and influences the mode properties of heralded states.
© 2011 Optical Society of America
Original Manuscript: December 14, 2010
Revised Manuscript: March 15, 2011
Manuscript Accepted: March 15, 2011
Published: April 15, 2011
K. Laiho, A. Christ, K. N. Cassemiro, and C. Silberhorn, "Testing spectral filters as Gaussian quantum optical channels," Opt. Lett. 36, 1476-1478 (2011)