Entangled femtosecond free induction signals in a cadmium sulfide crystal at room temperature

Abstract

Entangled free induction decay (EFID) femtosecond signals are experimentally observed for the first time at a wavelength of 790 nm in a cadmium sulfide (CdS) crystal in the two-photon absorption (TPA) regime upon excitation by two crossed (angle, 60°) laser beams. The sample emitted two EFID signals simul- taneously in opposite directions. The signals were diffracted by nonequilibrium electric polarization gratings induced by two laser beams in accordance with the laws of energy and momentum conservation. The possi- bility of exciting EFID signals in the three-photon absorption regime is discussed. © Allerton Press, Inc., 2012.