Spatial and spectral properties of the pulsed second-harmonic generation in a PP-KTP waveguide

Spatial and spectral properties of the pulsed second harmonic generation in a periodically-poled KTP waveguide exploiting simultaneously the first, second, and third harmonics of periodic nonlinear modulation are analyzed. Experimental results are interpreted using a model based on finite elements method. Correlations between spatial and spectral properties of the fundamental and second-harmonic fields are revealed. Individual nonlinear processes can be exploited combining spatial and spectral filtering. Also the influence of waveguide parameters to the second-harmonic spectra is addressed.Comment: 13 pages, 8 figure

Generation of polarization-entangled photon pairs in a Bragg reflection waveguide

We demonstrate experimentally that spontaneous parametric down-conversion in an AlGaAs semiconductor Bragg reflection waveguide can make for paired photons highly entangled in the polarization degree of freedom at the telecommunication wavelength of 1550 nm. The pairs of photons show visibility higher than 90% in several polarization bases and violate a Clauser-Horne-Shimony-Holt Bell-like inequality by more than 3 standard deviations. This represents a significant step toward the realization of efficient and versatile self pumped sources of entangled photon pairs on-chip.Comment: 9 pages, 4 figures, published versio

Spatial properties of twin-beam correlations at low-to high-intensity transition

It is shown that spatial correlation functions measured for correlated photon pairs at the single-photon level correspond to speckle patterns visible at high intensities. This correspondence is observed for the first time in one experimental setup by using different acquisition modes of an intensified CCD camera in low and high intensity regimes. The behavior of intensity auto-and cross-correlation functions in dependence on pumpbeam parameters including power and transverse profile is investigated

Optimal sub-Poissonian light generation from twin beams by photon-number resolving detectors

We generate nonclassical conditional states by exploiting the quantum correlations of multimode twin-beamstates endowed with a sizeable number of photons. A strong relation between the sub-shot-noise correlations exhibited by twin beams and the sub-Poissonian character of the conditional states is experimentally revealed, determining the optimal conditions for sub-Poissonian light generation

Characterizing the nonclassicality of mesoscopic optical twin-beam states

We present a robust tool to analyze nonclassical properties of multimode twin-beam states in the mesoscopic photon-number domain. The measurements are performed by direct detection. The analysis exploits three different nonclassicality criteria for detected photons exhibiting complementary behavior in the explored intensity regime. Joint signal-idler photon-number distributions and quasidistributions of integrated intensities are determined and compared with the corresponding distributions of detected photons. Experimental conditions optimal for nonclassical properties of twin-beam states are identified

Waves in intensity coherence of evolving intense twin beams

Strong correlations between the signal and idler beams imprinted during their generation dominantly determine the properties of twin beams. They are also responsible for the waves in intensity coherence observed in the wave-vector space of a twin beam propagating in a nonlinear crystal in the regime with pump depletion. These waves start to develop at certain twin-beam intensities and move from the signal- and idler-beam centers towards their tails. They manifest themselves via the change of coherence volume monitored in the far field by the measurement of local modified (g) over bar ((2)()) function, which acts as a sensitive and stable tool for investigating field intensity coherence

Luminescence-induced noise in single photon sources based on BBO crystals

Single-photon sources based on the process of spontaneous parametric down-conversion play a key role in various applied disciplines of quantum optics. We characterize the intrinsic luminescence of BBO crystals as a source of non-removable noise in quantum-optics experiments. By analysing its spectral and temporal properties together with its intensity, we evaluate the impact of luminescence on single-photon state preparation using spontaneous parametric down-conversion

Generation of sub-Poissonian non-Gaussian states from multimode twin beams by photon-number-resolving detectors

We generate sub-Poissonian non-Gaussian conditional states from pulsed multimode twin beams (TWBs) by measuring with photon-number-resolving detectors. Links among twin-beam non-classicality and the properties of the conditional states are discussed

Characterizing the nonclassicality of mesoscopic optical twin-beam states

We present a robust tool to analyze nonclassical properties of multimode twin-beam states in the mesoscopic photon-number domain. The measurements are performed by direct detection. The analysis exploits three different nonclassicality criteria for detected photons exhibiting complementary behavior in the explored intensity regime. Joint signal-idler photon-number distributions and quasidistributions of integrated intensities are determined and compared with the corresponding distributions of detected photons. Experimental conditions optimal for nonclassical properties of twin-beam states are identified.We present a robust tool to analyze nonclassical properties of multimode twin-beam states in the mesoscopic photon-number domain. The measurements are performed by direct detection. The analysis exploits three different nonclassicality criteria for detected photons exhibiting complementary behavior in the explored intensity regime. Joint signal-idler photon-number distributions and quasidistributions of integrated intensities are determined and compared with the corresponding distributions of detected photons. Experimental conditions optimal for nonclassical properties of twin-beam states are identified