Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2603.28519 · Optics Continuum

Photon-triplets for quantum optics generated by a phase-matched third-order difference-frequency mixing in a KTiOPO4 bulk crystal pumped at 532 nm

Gaspar Mougin-Trichon, Veronique Boutou, Corinne Felix, David Jegouso, Benoit Boulanger

quant-phphysics.opticsSubmitted Mar 30, 2026• Announced Mar 31, 2026• 0 citations
arXivHTMLPDF

Abstract

We report implementation and modelling of an efficient photon-triplets generation experiment based on a difference-frequency-mixing of two picosecond beams at 532 nm and 1491 nm in a type II phase-matched KTP crystal. The photon-triplets flux was measured as a function of the energy of the two incident beams using a coincidence protocol. A maximal flux of 11.6 photon-triplets per second was achieved. These experimental data were satisfactorily described by a semiclassical model based on the quantum fluctuations of vacuum and the classical equations of nonlinear optics.

Comments
4 pages, 1 table, 5 figures

Related papers

Experimental demonstration of a pure third-order optical parametric downconversion process

Julien Douady, Benoı̂t Boulanger

We report what is, to the best of our knowledge, the first experiment on third-order optical difference frequency generation. The nonlinear medium is a phase-matched KTiOPO4 crystal pumped at 532 and 1665 nm in the picosecond regime. The proposed experimental configuration leads to an efficient and pure cubic process, with generation of 4.5 microJ/pulse at 1474 nm. This result opens the way to new quantum experiments on three-photon Greenberger-Horne-Zeilinger entanglement.

Optics Letters•Dec 1, 2004•77 citations

Experimental demonstration and modeling of near-infrared nonlinear third-order triple-photon generation stimulated over one mode

J. Bertrand, Véronique Boutou, C. Félix +2 more

Triple Photon Generation (TPG) is a third-order nonlinear optical interaction in which a photon of energy ℏωp splits into three photons at ℏω1, ℏω2, and ℏω3, with ℏωp = ℏω1 + ℏω2 + ℏω3. The triplets possess different quantum signatures from those of photon pairs, with strong interest in quantum information. In the present study, we report the first experimental demonstration of TPG stimulated over one mode of the triplet, at ℏω1, whereas previous work on TPG concerned stimulation over two modes, at ℏω2 and ℏxω3. The nonlinear medium is a KTiOPO4 crystal pumped in the picosecond regime (15 ps, 10 Hz) at λp = 532 nm. The stimulation beam is emitted by a tunable optical parametric generator: the phase-matching was found at a stimulation wavelength λ1 = 1491 nm, the other two modes of the triplet being at λ2 = λ3 = 1654 nm in orthogonal polarizations. Using superconducting nanowire single photon detectors, the measurements of the polarizations and wavelength signatures of the two generated modes are in full agreement with calculations. It has been possible to generate a total number of photons per pulse on modes 2 and 3 up to 2 × 104, which corresponds to the generation of 104 triplets per pulse, or 105 triplets per second since the repetition rate is equal to 10 Hz. We interpreted these results in the framework of a model we developed on the basis of the nonlinear momentum operator in the Heisenberg representation under the undepleted pump and stimulation approximation.

arXiv:2412.19348•APL Quantum•Apr 25, 2025•5 citations

Semi-classical modelling of second-order spontaneous down-conversion measured over 10 decades of pump intensity in a type II phase-matched KTP crystal

Julien Bertrand, Véronique Boutou, Benoı̂t Boulanger

We performed a second-order spontaneous parametric down-conversion (SPDC) experiment in a Type II phase-matched KTiOPO4 crystal pumped at 532 nm giving birth to a signal beam at 1037 nm and an idler one at 1092 nm along the x-axis of the crystal. Three pump sources have been used: in the continuous-wave, nanosecond (200 ns, 1 kHz) and picosecond (15 ps, 10 Hz) regimes. That allowed us to cover a pump intensity range from 2.4 W.cm-2 to 3.7 GW.cm-2 which led to the generation of twin photons with a flux from 1.1x104 Hz to 1.2x1021 Hz, respectively, the corresponding quantum efficiencies being of 1.8x10-11 and 9.2x10-4. We identified two SPDC regimes regarding the pump intensity: one below 30 MW.cm-2 for which the flux increases linearly, and the other one above 30 MW.cm-2 for which the flux behaves exponentially. We proposed a semi-classical model under the undepleted pump approximation based on both the quantum fluctuations of vacuum for the seeding of the process and a propagation step ensured by classical fields, which allowed a satisfying description of these two regimes, with a much better agreement at high intensity than the quantum models based on the nonlinear momentum or the nonlinear Hamiltonian operators.

arXiv:2502.04815•Feb 7, 2025•0 citations

Triple-photon generation: comparison between theory and experiment

Fabien Gravier, Benoı̂t Boulanger

We conceived an optical generator leading to the production of 3×1013 triple photons per pulse with a full-width duration of 88ps at 1/e2, by using a third-order optical parametric interaction phase-matched in a KTP crystal and pumped at 532 nm. The triple photon generation is stimulated by two photons orthogonally polarized emitted by a homemade optical parametric oscillator emitting at 1665 nm. The energy generated at 1474 nm is well modelized by an analytical model based on Jacobi elliptic functions. These results open the way to new quantum measurement relative to Greenberger-Horne-Zeilinger state of light.

Journal of the Optical Society of America B•Dec 21, 2007•28 citations

Efficient energy conversion for cubic third-harmonic generation that is phase matched in KTiOPO_4

J. P. Fève, Benoı̂t Boulanger, Yannick Guillien

We demonstrate, for the first time to our knowledge, that efficient third-harmonic generation can be achieved with a cubic contribution much larger than the quadratic processes. An energy-conversion efficiency of 2.4% is achieved for cubic third-harmonic generation that is phase matched along the x axis of a KTiOPO(4) crystal by use of a picosecond fundamental laser emitting at 1618 nm. The associated cascading processes are only 10% of the pure cubic interaction, which is very suitable for study of the specific quantum optical correlations. Calculations of the third-harmonic generation conversion efficiency with respect to group-velocity dispersion and to the longitudinal Gaussian beam profile account well for our experimental results.

Optics Letters•Sep 15, 2000•36 citations

Demonstrating quantum properties of triple photons generated by $$\chi ^3$$ processes

Kamel Bencheikh, Marina F. B. Cenni, Enky Oudot +11 more

Abstract Triple-photon generation (TPG) is based on a third-order nonlinear optical interaction, which is the most direct way to produce pure quantum three-photon states. These states can exhibit three-body quantum correlations, and their statistics cannot be reproduced by any Gaussian statistics of coherent sources or optical parametric twin-photon generator, making them potentially useful for quantum information processing tasks such as quantum state distillation, quantum error-correction and universal quantum computing. Furthermore, the generation of entangled photon pairs heralded by the detection of a third photon can be used in advanced quantum communication protocols. We made the first experimental demonstration of TPG in 2004 using a bi-stimulation scheme in a bulk KTP crystal, followed by the quantum theory. The new challenges are now to achieve a spontaneous TPG and the corresponding quantum experiments and protocols using oriented ridge KTP waveguides, which ensures both birefringence phase-matching and light confinement. The waveguides are cut by a precision dicing saw. We recently performed their characterization using third-harmonic generation measurements, which showed their good quality. A rate of about 5 triplets per second is expected when pumping a 5-cm-long waveguide with a 5-W 532 nm beam in the CW regime. Such a spontaneous TPG exhibits low rate of triple photons, which makes the certification of quantum features hard. In this article, we review our theoretical and experimental work on TPG and the associated quantum modeling. We also develop theoretical tools for the certification of quantum features of spontaneous triple-photon states. Graphic abstract

The European Physical Journal D•Oct 1, 2022•12 citations
We report implementation and modelling of an efficient photon-triplets generation experiment based on a difference-frequency-mixing of two picosecond beams at 532 nm and 1491 nm in a type II phase-matched KTP crystal. The photon-triplets flux was measured as a function of the energy of the two incident beams using a coincidence protocol. A maximal flux of 11.6 photon-triplets per second was achieved. These experimental data were satisfactorily described by a semiclassical model based on the quantum fluctuations of vacuum and the classical equations of nonlinear optics.
Triple Photon Generation (TPG) is a third-order nonlinear optical interaction in which a photon of energy ℏωp splits into three photons at ℏω1, ℏω2, and ℏω3, with ℏωp = ℏω1 + ℏω2 + ℏω3. The triplets possess different quantum signatures from those of photon pairs, with strong interest in quantum information. In the present study, we report the first experimental demonstration of TPG stimulated over one mode of the triplet, at ℏω1, whereas previous work on TPG concerned stimulation over two modes, at ℏω2 and ℏxω3. The nonlinear medium is a KTiOPO4 crystal pumped in the picosecond regime (15 ps, 10 Hz) at λp = 532 nm. The stimulation beam is emitted by a tunable optical parametric generator: the phase-matching was found at a stimulation wavelength λ1 = 1491 nm, the other two modes of the triplet being at λ2 = λ3 = 1654 nm in orthogonal polarizations. Using superconducting nanowire single photon detectors, the measurements of the polarizations and wavelength signatures of the two generated modes are in full agreement with calculations. It has been possible to generate a total number of photons per pulse on modes 2 and 3 up to 2 × 104, which corresponds to the generation of 104 triplets per pulse, or 105 triplets per second since the repetition rate is equal to 10 Hz. We interpreted these results in the framework of a model we developed on the basis of the nonlinear momentum operator in the Heisenberg representation under the undepleted pump and stimulation approximation.
We performed a second-order spontaneous parametric down-conversion (SPDC) experiment in a Type II phase-matched KTiOPO4 crystal pumped at 532 nm giving birth to a signal beam at 1037 nm and an idler one at 1092 nm along the x-axis of the crystal. Three pump sources have been used: in the continuous-wave, nanosecond (200 ns, 1 kHz) and picosecond (15 ps, 10 Hz) regimes. That allowed us to cover a pump intensity range from 2.4 W.cm-2 to 3.7 GW.cm-2 which led to the generation of twin photons with a flux from 1.1x104 Hz to 1.2x1021 Hz, respectively, the corresponding quantum efficiencies being of 1.8x10-11 and 9.2x10-4. We identified two SPDC regimes regarding the pump intensity: one below 30 MW.cm-2 for which the flux increases linearly, and the other one above 30 MW.cm-2 for which the flux behaves exponentially. We proposed a semi-classical model under the undepleted pump approximation based on both the quantum fluctuations of vacuum for the seeding of the process and a propagation step ensured by classical fields, which allowed a satisfying description of these two regimes, with a much better agreement at high intensity than the quantum models based on the nonlinear momentum or the nonlinear Hamiltonian operators.
We conceived an optical generator leading to the production of 3×1013 triple photons per pulse with a full-width duration of 88ps at 1/e2, by using a third-order optical parametric interaction phase-matched in a KTP crystal and pumped at 532 nm. The triple photon generation is stimulated by two photons orthogonally polarized emitted by a homemade optical parametric oscillator emitting at 1665 nm. The energy generated at 1474 nm is well modelized by an analytical model based on Jacobi elliptic functions. These results open the way to new quantum measurement relative to Greenberger-Horne-Zeilinger state of light.
We demonstrate, for the first time to our knowledge, that efficient third-harmonic generation can be achieved with a cubic contribution much larger than the quadratic processes. An energy-conversion efficiency of 2.4% is achieved for cubic third-harmonic generation that is phase matched along the x axis of a KTiOPO(4) crystal by use of a picosecond fundamental laser emitting at 1618 nm. The associated cascading processes are only 10% of the pure cubic interaction, which is very suitable for study of the specific quantum optical correlations. Calculations of the third-harmonic generation conversion efficiency with respect to group-velocity dispersion and to the longitudinal Gaussian beam profile account well for our experimental results.
Demonstrating quantum properties of triple photons generated by χ3\chi ^3χ3 processes
Abstract Triple-photon generation (TPG) is based on a third-order nonlinear optical interaction, which is the most direct way to produce pure quantum three-photon states. These states can exhibit three-body quantum correlations, and their statistics cannot be reproduced by any Gaussian statistics of coherent sources or optical parametric twin-photon generator, making them potentially useful for quantum information processing tasks such as quantum state distillation, quantum error-correction and universal quantum computing. Furthermore, the generation of entangled photon pairs heralded by the detection of a third photon can be used in advanced quantum communication protocols. We made the first experimental demonstration of TPG in 2004 using a bi-stimulation scheme in a bulk KTP crystal, followed by the quantum theory. The new challenges are now to achieve a spontaneous TPG and the corresponding quantum experiments and protocols using oriented ridge KTP waveguides, which ensures both birefringence phase-matching and light confinement. The waveguides are cut by a precision dicing saw. We recently performed their characterization using third-harmonic generation measurements, which showed their good quality. A rate of about 5 triplets per second is expected when pumping a 5-cm-long waveguide with a 5-W 532 nm beam in the CW regime. Such a spontaneous TPG exhibits low rate of triple photons, which makes the certification of quantum features hard. In this article, we review our theoretical and experimental work on TPG and the associated quantum modeling. We also develop theoretical tools for the certification of quantum features of spontaneous triple-photon states. Graphic abstract