Negative group velocities in cascading nonlinear optical interactions
INFM, Dipartimento di Fisica, Politecnico di Milano
Piazza L. da Vinci, 32 I-20133 Milano (Italy)
Accepted: 19 July 2002
Cascading second-order nonlinear processes in quasi-phase matching (QPM) nonlinear crystals can strongly affect the effective group velocity of a propagating optical pulse, leading to superluminal or even negative transit times. With reference to a QPM LiNbO3 parametric amplifier, we propose a device in which the transit time of spectrally narrow optical pulses at signal wavelength of 1.55 μm can be controlled by the pump intensity and may be pushed to negative values under experimentally achievable pump power levels.
PACS: 42.65.Yj – Optical parametric oscillators and amplifiers / 42.65.Ky – Harmonic generation, frequency conversion / 03.65.Xp – Tunneling, traversal time, quantum Zeno dynamics
© EDP Sciences, 2002