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

Journal of Optics

Measurement of the wavefunction for a biphoton state with homodyne detection using least squares estimation

Yashuai Han, Daohua Wu, Katsuyuki Kasai, Lirong Wang, Masayoshi Watanabe, Yun Zhang

Published Dec 19, 2019• 4 citations
Publisher

Abstract

Abstract We report the measurement of wave function for a biphoton state with continuous variables (CV) by homodyne detection. The biphoton interference occurs on an optical parametric oscillator, which is seeded with a coherent state. A set of second-order correlation function values for the output field are recorded when the intensity coherent state is varied. The wave function, which includes both magnitude and argument for a complex parameter of the biphoton state, is reconstructed using the least square estimation method. This may introduce another approach to characterizing a biphoton state in the regime of CV.

DOI
10.1088/2040-8986/ab6422

Related papers

Temporal Quantum-State Tomography of Narrowband Biphotons

Chi Shu, Peng Chen, Shengwang Du +2 more

We demonstrate a technique of quantum-state tomography for measuring the complex temporal wave function of narrowband biphotons with polarization-dependent and time-resolved two-photon interference. While the amplitude function of the biphoton waveform is directly related to the second-order correlation function which is determined by the two-photon coincidence measurement, the phase function is retrieved from six sets of time-resolved two-photon interference measurements projected onto different polarization subspaces. We apply this technique to experimentally reconstruct the temporal quantum states of the narrow-band biphotons generated from the spontaneous four-wave mixing in cold atoms. As compared with the homodyne detection, our method doesn't require any external phase reference.

•Jan 1, 2015•0 citations

Measurement and Shaping of Biphoton Spectral Wave Functions

Nora Tischler, Alexander Büse, L. G. Helt +5 more

In this work we present a simple method to reconstruct the complex spectral wave function of a biphoton, and hence gain complete information about the spectral and temporal properties of a photon pair. The technique, which relies on quantum interference, is applicable to biphoton states produced with a monochromatic pump when a shift of the pump frequency produces a shift in the relative frequencies contributing to the biphoton. We demonstrate an example of such a situation in type-II parametric down conversion allowing arbitrary paraxial spatial pump and detection modes. Moreover, our test cases demonstrate the possibility to shape the spectral wave function. This is achieved by choosing the spatial mode of the pump and of the detection modes, and takes advantage of spatiotemporal correlations.

arXiv:1503.08629•Physical Review Letters•Nov 3, 2015•31 citations

Interferometric Measurement of the Biphoton Wave Function

Federica A. Beduini, Joanna A. Zielińska, Vito Giovanni Lucivero +2 more

Interference between an unknown two-photon state (a "biphoton") and the two-photon component of a reference state gives a phase-sensitive arrival-time distribution containing full information about the biphoton temporal wave function. Using a coherent state as a reference, we observe this interference and reconstruct the wave function of single-mode biphotons from a low-intensity narrow band squeezed vacuum state.

arXiv:1407.7683•Physical Review Letters•Oct 31, 2014•33 citations

Measuring Photon Antibunching from Continuous Variable Sideband Squeezing

Nicolai B. Grosse, Thomas Symul, Magdalena Stobińska +2 more

We present a technique for measuring the second-order coherence function g(2)(tau) of light using a Hanbury Brown-Twiss intensity interferometer modified for homodyne detection. The experiment was performed entirely in the continuous-variable regime at the sideband frequency of a bright carrier field. We used the setup to characterize g(2)(tau) for thermal and coherent states and investigated its immunity to optical loss. We measured g(2)(tau) of a displaced-squeezed state and found a best antibunching statistic of g(2)(0)=0.11+/-0.18.

arXiv:quant-ph/0609033•Physical Review Letters•Apr 13, 2007•72 citations

Quantum characterization of bipartite Gaussian states

Daniela Buono, Gaetano Nocerino, Virginia D’Auria +3 more

Gaussian bipartite states are basic tools for the realization of quantum information protocols with continuous variables. Their complete characterization is obtained by the reconstruction of the corresponding covariance matrix. Here we describe in detail and experimentally demonstrate a robust and reliable method to fully characterize bipartite optical Gaussian states by means of a single homodyne detector. We have successfully applied our method to the bipartite states generated by a sub-threshold type-II optical parametric oscillator which produces a pair of thermal cross-polarized entangled cw frequency degenerate beams. The method provides a reliable reconstruction of the covariance matrix and allows us to retrieve all the physical information about the state under investigation. These include observable quantities, such as energy and squeezing, as well as nonobservable ones such as purity, entropy, and entanglement. Our procedure also includes advanced tests for the Gaussianity of the state and, overall, represents a powerful tool to study the bipartite Gaussian state from the generation stage to the detection one.

arXiv:1006.0837•Journal of the Optical Society of America B•Apr 28, 2010•48 citations

Quantum Statistics of the Squeezed Vacuum by Measurement of the Density Matrix in the Number State Representation

Stephan Schiller, Gerd Breitenbach, Silvania F. Pereira +2 more

We report the reconstruction of the quantum state of squeezed vacuum generated by a continuous-wave optical parametric amplifier. Homodyne detection and tomographic reconstruction methods were used to obtain the density matrix in the Fock (number state) representation. The photon number distribution exhibits odd-even oscillations, a manifestation of the photon pair production in the second-order nonlinear medium.

Physical Review Letters•Sep 30, 1996•231 citations
Abstract We report the measurement of wave function for a biphoton state with continuous variables (CV) by homodyne detection. The biphoton interference occurs on an optical parametric oscillator, which is seeded with a coherent state. A set of second-order correlation function values for the output field are recorded when the intensity coherent state is varied. The wave function, which includes both magnitude and argument for a complex parameter of the biphoton state, is reconstructed using the least square estimation method. This may introduce another approach to characterizing a biphoton state in the regime of CV.
We demonstrate a technique of quantum-state tomography for measuring the complex temporal wave function of narrowband biphotons with polarization-dependent and time-resolved two-photon interference. While the amplitude function of the biphoton waveform is directly related to the second-order correlation function which is determined by the two-photon coincidence measurement, the phase function is retrieved from six sets of time-resolved two-photon interference measurements projected onto different polarization subspaces. We apply this technique to experimentally reconstruct the temporal quantum states of the narrow-band biphotons generated from the spontaneous four-wave mixing in cold atoms. As compared with the homodyne detection, our method doesn't require any external phase reference.
In this work we present a simple method to reconstruct the complex spectral wave function of a biphoton, and hence gain complete information about the spectral and temporal properties of a photon pair. The technique, which relies on quantum interference, is applicable to biphoton states produced with a monochromatic pump when a shift of the pump frequency produces a shift in the relative frequencies contributing to the biphoton. We demonstrate an example of such a situation in type-II parametric down conversion allowing arbitrary paraxial spatial pump and detection modes. Moreover, our test cases demonstrate the possibility to shape the spectral wave function. This is achieved by choosing the spatial mode of the pump and of the detection modes, and takes advantage of spatiotemporal correlations.
We present a technique for measuring the second-order coherence function g(2)(tau) of light using a Hanbury Brown-Twiss intensity interferometer modified for homodyne detection. The experiment was performed entirely in the continuous-variable regime at the sideband frequency of a bright carrier field. We used the setup to characterize g(2)(tau) for thermal and coherent states and investigated its immunity to optical loss. We measured g(2)(tau) of a displaced-squeezed state and found a best antibunching statistic of g(2)(0)=0.11+/-0.18.
Gaussian bipartite states are basic tools for the realization of quantum information protocols with continuous variables. Their complete characterization is obtained by the reconstruction of the corresponding covariance matrix. Here we describe in detail and experimentally demonstrate a robust and reliable method to fully characterize bipartite optical Gaussian states by means of a single homodyne detector. We have successfully applied our method to the bipartite states generated by a sub-threshold type-II optical parametric oscillator which produces a pair of thermal cross-polarized entangled cw frequency degenerate beams. The method provides a reliable reconstruction of the covariance matrix and allows us to retrieve all the physical information about the state under investigation. These include observable quantities, such as energy and squeezing, as well as nonobservable ones such as purity, entropy, and entanglement. Our procedure also includes advanced tests for the Gaussianity of the state and, overall, represents a powerful tool to study the bipartite Gaussian state from the generation stage to the detection one.