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

Realizing Grover Search in Nonlinear Optical Crystals

Murphy Yuezhen Niu

Published Mar 22, 2016• 0 citations
OpenAlex

Abstract

We demonstrate the first theoretical model of a generalized Grover search in non-linear quantum optics through spontaneous parametric down-conversion. The quantum search algorithm enables us to overcome the low conversion efficiency limit of conventional phase matching processes. Extending our method to multi-photon levels, a scalable Grover search can be realized with novel fabrication designs.

Related papers

Substrate-Driven Modulation of Photon Pair Generation in Quantum Optical Metasurfaces

Alberto Paniate, Ivano Ruo Berchera, Marco Genovese +1 more

Most modern quantum light sources are based on spontaneous parametric down-conversion (SPDC) in bulk non-linear crystals, with strict phase-matching requirements that limit their design flexibility and the range of two-photon states produced. Recent research has focused on generating quantum light via SPDC with metasurfaces [1], i.e. array of nanoresonators with sub-wavelength dimensions. At this scale, SPDC becomes independent of phase matching, allowing the use of materials with greater nonlinear susceptibility and enabling efficient photon generation with tailored properties for the angular and spectral distribution and polarization.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 23, 2025•0 citations

Unity-Efficiency Parametric Down-Conversion via Amplitude Amplification

Murphy Yuezhen Niu, Barry C. Sanders, Franco N. C. Wong +1 more

We propose an optical scheme, employing optical parametric down-converters interlaced with nonlinear sign gates (NSGs), that completely converts an n-photon Fock-state pump to n signal-idler photon pairs when the down-converters' crystal lengths are chosen appropriately. The proof of this assertion relies on amplitude amplification, analogous to that employed in Grover search, applied to the full quantum dynamics of single-mode parametric down-conversion. When we require that all Grover iterations use the same crystal, and account for potential experimental limitations on crystal-length precision, our optimized conversion efficiencies reach unity for 1≤n≤5, after which they decrease monotonically for n values up to 50, which is the upper limit of our numerical dynamics evaluations. Nevertheless, our conversion efficiencies remain higher than those for a conventional (no NSGs) down-converter.

arXiv:1603.06857•Physical Review Letters•Mar 23, 2017•6 citations

Source of Photon Pairs Using Spontaneous Parametric Down -Conversion Process

Mubarack Ahmed, Alfred Adutwum Amponsah, Emmanuel Akweittey +1 more

The importance of photon pair generation can never be overemphasized. It has formed the basis of most fundamental quantum optical experiments like Bell-experiments, quantum teleportation and entanglement swapping. However for considerable number of years Quantum Mechanics in general has remained largely theoretical and within the four corners of laboratories. Quantum Key Distribution is one of the first quantum applications to break this barrier. It provides us with unconditionally secured communication by providing us with efficient alternative to classical cryptography. This study forms part of the effort in realizing efficient way of generating photon pairs through the Spontaneous Parametric Down-Conversion process using a nonlinear crystal cut for type-I phase matching. After generating the photon pairs, the paper examined how they can be detected efficiently. We measured the rate of single photon generation (up to 200 kHz) as well as the rate at which they are detected in coincidence (150 coincidences per second). We further investigated a quantum interference effect (the Hong-Ou-Mandel effect) which classical wave theory has failed to describe. This effect has numerous applications in scalable quantum networks and in linear quantum computing. Finally, a remarkable conversion efficiency of 2.2

International journal of innovation and applied studies•Nov 15, 2014•0 citations

Linear Optical Implementation of Grover's Quantum Search Algorithm

Lan Xu

Based on the single photon representation of qubits,this paper proposes an optical implementation for the Grover's quantum search algorithm by using linear optical elements.It can also be expected to widely use this method to realize more general quantum networks of many-qubit Grover's algorithm.

Journal of Hunan First Normal University•Jan 1, 2011•0 citations

Influence of Nonlinear Crystal Properties on Entanglement Generation in Spontaneous Parametric Down-Conversion (SPDC) Sources

Hiba Chakir, Farid Abdi, F. M. Abbou

The generation of entangled photon pairs through spontaneous parametric down conversion (SPDC) is widely used and considered one of the key entanglement generation techniques in quantum optics. The quality of the entanglement produced depends significantly on the physical properties of the nonlinear crystal employed in the SPDC process. In this study, we investigate the influence of the crystal parameters such as phase matching configurations on the degree of entanglement. Our results demonstrate the importance of crystal selection for achieving highly entangled photon sources, which are essential for applications in quantum communication and quantum information.

Materials science forum•Aug 4, 2026•0 citations

Generation of spectrally factorable photon pairs via multi-order quasi-phase-matched spontaneous parametric downconversion

Fumihiro Kaneda, Jo Oikawa, Masahiro Yabuno +5 more

For advanced quantum information technology, sources of photon pairs in quantum mechanically factorable states are of great importance for realizing high-fidelity photon-photon quantum gate operations. Here we experimentally demonstrate a technique to produce spectrally factorable photon pairs utilizing multi-order quasi-phase-matching (QPM) conditions in spontaneous parametric downconversion (SPDC). In our scheme, a spatial nonlinearity profile of a nonlinear optical crystal is shaped with current standard poling techniques, and the associated phase-matching function can be approximated to a Gaussian form. By the measurement of a phase-matching function and the second-order autocorrelation function, we demonstrate that telecom-band photon pairs produced by our custom-poled crystal are highly factorable with > 95% single-photon purity.

arXiv:2111.10981•Nov 22, 2021•5 citations
We demonstrate the first theoretical model of a generalized Grover search in non-linear quantum optics through spontaneous parametric down-conversion. The quantum search algorithm enables us to overcome the low conversion efficiency limit of conventional phase matching processes. Extending our method to multi-photon levels, a scalable Grover search can be realized with novel fabrication designs.
Most modern quantum light sources are based on spontaneous parametric down-conversion (SPDC) in bulk non-linear crystals, with strict phase-matching requirements that limit their design flexibility and the range of two-photon states produced. Recent research has focused on generating quantum light via SPDC with metasurfaces [1], i.e. array of nanoresonators with sub-wavelength dimensions. At this scale, SPDC becomes independent of phase matching, allowing the use of materials with greater nonlinear susceptibility and enabling efficient photon generation with tailored properties for the angular and spectral distribution and polarization.
We propose an optical scheme, employing optical parametric down-converters interlaced with nonlinear sign gates (NSGs), that completely converts an n-photon Fock-state pump to n signal-idler photon pairs when the down-converters' crystal lengths are chosen appropriately. The proof of this assertion relies on amplitude amplification, analogous to that employed in Grover search, applied to the full quantum dynamics of single-mode parametric down-conversion. When we require that all Grover iterations use the same crystal, and account for potential experimental limitations on crystal-length precision, our optimized conversion efficiencies reach unity for 1≤n≤5, after which they decrease monotonically for n values up to 50, which is the upper limit of our numerical dynamics evaluations. Nevertheless, our conversion efficiencies remain higher than those for a conventional (no NSGs) down-converter.
The importance of photon pair generation can never be overemphasized. It has formed the basis of most fundamental quantum optical experiments like Bell-experiments, quantum teleportation and entanglement swapping. However for considerable number of years Quantum Mechanics in general has remained largely theoretical and within the four corners of laboratories. Quantum Key Distribution is one of the first quantum applications to break this barrier. It provides us with unconditionally secured communication by providing us with efficient alternative to classical cryptography. This study forms part of the effort in realizing efficient way of generating photon pairs through the Spontaneous Parametric Down-Conversion process using a nonlinear crystal cut for type-I phase matching. After generating the photon pairs, the paper examined how they can be detected efficiently. We measured the rate of single photon generation (up to 200 kHz) as well as the rate at which they are detected in coincidence (150 coincidences per second). We further investigated a quantum interference effect (the Hong-Ou-Mandel effect) which classical wave theory has failed to describe. This effect has numerous applications in scalable quantum networks and in linear quantum computing. Finally, a remarkable conversion efficiency of 2.2
The generation of entangled photon pairs through spontaneous parametric down conversion (SPDC) is widely used and considered one of the key entanglement generation techniques in quantum optics. The quality of the entanglement produced depends significantly on the physical properties of the nonlinear crystal employed in the SPDC process. In this study, we investigate the influence of the crystal parameters such as phase matching configurations on the degree of entanglement. Our results demonstrate the importance of crystal selection for achieving highly entangled photon sources, which are essential for applications in quantum communication and quantum information.
For advanced quantum information technology, sources of photon pairs in quantum mechanically factorable states are of great importance for realizing high-fidelity photon-photon quantum gate operations. Here we experimentally demonstrate a technique to produce spectrally factorable photon pairs utilizing multi-order quasi-phase-matching (QPM) conditions in spontaneous parametric downconversion (SPDC). In our scheme, a spatial nonlinearity profile of a nonlinear optical crystal is shaped with current standard poling techniques, and the associated phase-matching function can be approximated to a Gaussian form. By the measurement of a phase-matching function and the second-order autocorrelation function, we demonstrate that telecom-band photon pairs produced by our custom-poled crystal are highly factorable with > 95% single-photon purity.