Spectral distinguishability in ultrafast parametric down-conversion

Grice, Warren P.; Erdmann, Reinhard; Walmsley, Ian A.; Branning, David

doi:10.1103/physreva.57.r2289

Cited by 75 publications

(42 citation statements)

References 13 publications

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“…The short pulse duration implies a wide distribution of pump frequencies. In combination with the dispersion relations of the nonlinear optical material this leads to entanglement of the polarization degree of freedom with the spectral properties of the down-converted photons [12]. For the purpose of generating pure entangled states in only one variable, this is generally detrimental, manifesting itself as a degree of mixedness when only the polarization is considered (with the exception of the work reported in [13]).…”

Section: Introductionmentioning

confidence: 99%

Joint spectrum mapping of polarization entanglement in spontaneous parametric down-conversion

et al. 2007

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Polarization-entangled photon pairs can be efficiently prepared into pure Bell states with a high fidelity via type-II spontaneous parametric down-conversion (SPDC) of narrow-band pump light. However, the use of femtosecond pump pulses to generate multi-photon states with precise timing often requires spectral filtering to maintain a high quality of polarization entanglement. This typically reduces the efficiency of photon pair collection. We experimentally map the polarization correlations of photon pairs from such a source over a range of down-converted wavelengths with a high spectral resolution and find strong polarization correlations everywhere. A spectrally dependent imbalance between contributions from the two possible decay paths of SPDC is identified as the reason for a reduction in entanglement quality observed with femtosecond pump pulses. Our spectral measurements allow to predict the polarization correlations for arbitrary filter profiles when the frequency degree of freedom of the photon pairs is ignored.

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Section: Introductionmentioning

confidence: 99%

Joint spectrum mapping of polarization entanglement in spontaneous parametric down-conversion

et al. 2007

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“…Unfortunately, femtosecond pulse pumped SPDC shows relatively poor quantum interference visibilities (Keller and Rubin, 1997). The following methods are used to increase the quantum interference visibility: (i) a thin nonlinear crystal (Sergienko et al, 1999), (ii) narrow-band spectral filters in front of detectors, as shown above (Grice and Walmsley, 1997;Grice et al, 1998;Di Giuseppe et al, 1997), or (iii) an interferometric technique (Branning et al, 1999(Branning et al, , 2000 without spectral and amplitude post-selection, which was making the spectral wave function of the two photons much more symmetric. 25 The first two methods reduce the intensity of the entangled photon pairs significantly and cannot achieve perfect overlap of the two-photon amplitudes.…”

Section: New Methodsmentioning

confidence: 99%

Multiphoton entanglement and interferometry

Bourennane

Eibl

Gaertner

et al. 2003

Fortschritte der Physik

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Multi-photon interference reveals strictly non-classical phenomena. Its applications range from fundamental tests of quantum mechanics to photonic quantum information processing, where a significant fraction of key experiments achieved so far comes from multi-photon state manipulation. We review the progress, both theoretical and experimental, of this rapidly advancing research. The emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication (e.g., quantum teleportation, entanglement purification and quantum repeater), and quantum computation with linear optics. We shall limit the scope of our review to "few photon" phenomena involving measurements of discrete observables.

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“…However, the visibility of type-II entangled photons sources operated in pulsed mode is limited. The visibility depends strongly on the thickness of the nonlinear crystal and the temporal and spectral widths of the pump beam [11,12,13,14,15]. Due to the birefringent nature of the crystal, the down converted photons travel inside the crystal at different speeds.…”

Section: Introductionmentioning

confidence: 99%

“…This removes some, but not all, of the distinguishing information. Further improvements may be realized through the use of a thin non-linear crystal [15,16] or narrow-band filters [14] which increase the coherence time. However, both methods reduce the available entangled photon flux reaching the detectors.…”

Section: Introductionmentioning

confidence: 99%

Cascaded ultrabright source of polarization-entangled photons

Bitton

Grice²,

Moreau³

et al. 2002

Phys. Rev. A

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A new ultra bright pulsed source of polarization entangled photons has been realized using type-II phase matching in spontaneous parametric down conversion process in two cascaded crystals. The optical axes of the crystals are aligned in such a way that the extraordinarily (ordinarily) polarized cone from one crystal overlaps with the ordinarily (extraordinarily) polarized cone from the second crystal. This spatial overlapping removes the association between the polarization and the output angle of the photons that exist in a single type-II down conversion process. Hence, entanglement of photons originating from any point on the output cones is possible if a suitable optical delay line is used. This delay line is particularly simple and easy to implement.

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Spectral distinguishability in ultrafast parametric down-conversion

Cited by 75 publications

References 13 publications

Joint spectrum mapping of polarization entanglement in spontaneous parametric down-conversion

Joint spectrum mapping of polarization entanglement in spontaneous parametric down-conversion

Multiphoton entanglement and interferometry

Cascaded ultrabright source of polarization-entangled photons

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