Giant twin beams directed by the Poynting vector

01.01.2016, 00:00

Newsletter 9

In high-gain parametric down-conversion, the strongest emission is along the pump beam, namely along its energy propagation direction. If the pump undergoes spatial walk-off, a certain direction is selected out of the familiar ‘rainbow’ of rings – the one given by the pump Poynting vector. Along this direction, we observe a strong spatially single-mode beam, with its twin generated along the phase matching direction. A similar effect occurs in the temporal domain: the emission is strongly enhanced for wavelengths that are group-velocity matched with the pump. In both cases, an enhancement of more than two orders of magnitude is observed. Based on the spatial walk-off effect, we have constructed a new type of optical parametric generator. Up to 30% of the pump photons are converted into the signal beam, which is nearly single-mode spatially and tunable over the range 1400-1700 nm.  Conveniently, its twin is in the visible wavelength range and is anti-correlated with the signal beam in wavelength and correlated in photon number.

Contact: maria.chekhova(at)mpl.mpg(dot)de
Group: Leuchs Division (Quarad)
Reference: A. M. Perez et al., Nature Comm. 6, 7707, (2015).