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

Quantum Communications and Quantum Imaging

Non-classical correlation of two-mode squeezed light in asymmetric optical-loss conditions

Genta Masada

Published Sep 18, 2018• 1 citation
Publisher

Abstract

Quantum illumination is an attractive scheme for target detection utilizing quantum entanglement to improve error probability of discrimination for target presence or absence even in a lossy and noisy environment. In the quantum illumination with two-mode squeezed vacuum states, one of the entangled beams, a signal beam is transmitted towards a lossy optical medium. And the other beam, a reference beam is directly sent to receiver with a lossless channel. So, the entangled light beams are affected by the asymmetric optical loss. In this work we calculate the correlation variance of quadrature phase amplitudes of two-mode squeezed light under the asymmetric optical-loss conditions and discuss its non-classical correlation based on Duan’s and Simon’s inseparability criterion. The asymmetric optical loss sensitively increases the correlation variance and violates the inseparability criterion. In this work we consider asymmetric two-mode squeezed light as an initial state where the signal beam has larger quadrature phase amplitudes than the reference beam. After exposition to the asymmetric optical loss only the quadrature phase amplitudes of the signal beam is attenuated and become comparable to those of the reference beam. As a result it is expected that the asymmetric two-mode squeezed light has an ability to compensate the effect of the asymmetric optical loss and can maintain the inseparability criterion in the sense of Duan and Simon.

DOI
10.1117/12.2321044

Related papers

Verification of quantum entanglement of two-mode squeezed light source towards quantum radar and imaging

Genta Masada

Two-mode squeezed light is an effective resource for quantum entanglement and shows a non-classical correlation between each optical mode. We are developing a two-mode squeezed light source to explore the possibility of quantum radar based on the quantum illumination theory. It is expected that the error probability for discrimination of target presence or absence is improved even in a lossy and noisy environment. We are also expecting to apply two-mode squeezed light source to quantum imaging. In this work we generated two-mode squeezed light and verify its quantum entanglement property towards quantum radar and imaging. Firstly we generated two independent single-mode squeezed light beams utilizing two sub-threshold optical parametric oscillators which include periodically-polled potassium titanyl phosphate crystals for the second order nonlinear interaction. Two single-mode squeezed light beams are combined using a half mirror with the relative optical phase of 90◦ between each optical field. Then entangled two-mode squeezed light beams can be generated. We observes correlation variances between quadrature phase amplitudes in entangled two-mode fields by balanced homodyne measurement. Finally we verified quantum entanglement property of two-mode squeezed light source based on Duan’s and Simon’s inseparability criterion.

Quantum Communications and Quantum Imaging•Aug 30, 2017•5 citations

Two-mode squeezed light source for quantum illumination and quantum imaging II

Genta Masada

Two-mode squeezed light is a macroscopic quantum entangled state of electro-magnetic fields and shows non-classical correlation between quadrature phase amplitudes in each optical mode. In this work the author is developing a high-quality two-mode squeezed light source for exploring the possibility of a quantum radar system based on a quantum illumination method and also expecting to apply it to quantum imaging. Two-mode squeezed light can be generated by combining two independent single-mode squeezed light beams using a beam splitter with a relative optical phase of 90 degrees between them. In current experimental progress the author developed two sub-threshold optical parametric oscillators to generate single-mode squeezed light beams. In the actual quantum radar or quantum imaging system, a turbulent atmosphere degrades quantum entanglement of a light source and affects performance of target detection. An optical loss is one of the simplest and most probable examples of environmental factors. In this work an evaluation method for quantum entanglement of two-mode squeezed light source is developed with consideration for the optical loss based on Duan's inseparability criteria.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 13, 2016•4 citations

Quantum illumination using non-Gaussian states with conditional measurements

Huan Zhang, Ying Xia, Wei Ye +2 more

Quantum illumination is a quantum sensing protocol primarily used for object detection, which aims to detect the presence of a target with low reflectivity in the free space using quantum light fields. Here we investigate a quantum illumination scheme using an entangled light source by performing non-Gaussian operations on the two-mode squeezed vacuum (TMSV) state in order to reduce the detection error probability and meanwhile improve the signal-to-noise (SNR) ratio. We demonstrate that under the same squeezing parameter, the non-Gaussian operations can significantly reduce the detection error rate compared with the original TMSV state. Under the same average signal photon number, both the TMSV states with and without non-Gaussian operations can provide smaller error rate than that of the coherent state. In addition, we consider the balanced homodyne detection on idler and return signal photons as joint measurement and find that non-Gaussian operations can enhance the SNR of target detection by about 6--9 dB compared with that using TMSV. These results here demonstrate the advantage of the non-Gaussian entangled source in quantum illumination protocol and can find potential applications in target detection in noisy environment.

Physical Review A•Jun 28, 2024•12 citations

Minimum error probability of quantum illumination

Giacomo De Palma, Johannes Borregaard

Quantum illumination is a technique for detecting the presence of a target in a noisy environment by means of a quantum probe. We prove that the two-mode squeezed vacuum state is the optimal probe for quantum illumination in the scenario of asymmetric discrimination, where the goal is to minimize the decay rate of the probability of a false positive with a given probability of a false negative. Quantum illumination with two-mode squeezed vacuum states offers a 6 dB advantage in the error probability exponent compared to illumination with coherent states. Whether more advanced quantum illumination strategies may offer further improvements had been a longstanding open question. Our fundamental result proves that nothing can be gained by considering more exotic quantum states, such as, e.g., multimode entangled states. Our proof is based on a fundamental entropic inequality for the noisy quantum Gaussian attenuators. We also prove that without access to a quantum memory, the optimal probes for quantum illumination are the coherent states.

arXiv:1802.02158•Physical Review A•Jul 2, 2018•70 citations

Two-mode squeezed light source for quantum illumination and quantum imaging

Genta Masada

We started to research quantum illumination radar and quantum imaging by utilizing high quality continuous-wave two-mode squeezed light source as a quantum entanglement resource. Two-mode squeezed light is a macroscopic quantum entangled state of the electro-magnetic field and shows strong correlation between quadrature phase amplitudes of each optical field. One of the most effective methods to generate two-mode squeezed light is combining two independent single-mode squeezed lights by using a beam splitter with relative phase of 90 degrees between each optical field. As a first stage of our work we are developing two-mode squeezed light source for exploring the possibility of quantum illumination radar and quantum imaging. In this article we introduce current development of experimental investigation of single-mode squeezed light. We utilize a sub-threshold optical parametric oscillator with bow-tie configuration which includes a periodically-polled potassium titanyl phosphate crystal as a nonlinear optical medium. We observed the noise level of squeezed quadrature −3.08±0.13 dB and anti-squeezed quadrature at 9.29±0.13 dB, respectively. We also demonstrated the remote tuning of squeezing level of the light source which leads to the technology for tuning the quantum entanglement in order to adapt to the actual environmental condition.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 1, 2015•6 citations

Enhanced quantum illumination of a lossy target: A sequential interaction model

Shilpi Srivastava, Shubhrangshu Dasgupta

Quantum illumination (QI) exploits quantum correlations to detect weakly reflecting targets embedded in noisy environments with higher sensitivity than classical illumination (CI). We investigate the effectiveness of QI in a realistic setting in which the signal sequentially interacts with a noisy environment and a lossy target. The target is considered at a temperature distinct from its surroundings, while both the interactions are modeled as an action of independent beam splitters with different reflectivities. The detection performance is quantified using the signal-to-noise ratio (SNR) and the quantum Chernoff bound (QCB), the latter providing an upper bound on the error probability. The performance of the Gaussian two-mode squeezed state (TMSS) is compared with that of the optimal classical protocol based on coherent states (CS). The proposed model shows that TMSS consistently achieves a higher SNR than CS for a low-reflectivity target and an arbitrary phase change and remains robust against thermal noise. Furthermore, a sufficiently lower QCB is obtained for TMSS than in previously reported results, indicating greater distinguishability between the presence and absence of the target. These findings underscore the role of realistic modeling in improving QI-based detection of lossy targets, with potential relevance to quantum radar and lidar systems.

quant-pharXiv:2604.12381•Apr 15, 2026•0 citations
Quantum illumination is an attractive scheme for target detection utilizing quantum entanglement to improve error probability of discrimination for target presence or absence even in a lossy and noisy environment. In the quantum illumination with two-mode squeezed vacuum states, one of the entangled beams, a signal beam is transmitted towards a lossy optical medium. And the other beam, a reference beam is directly sent to receiver with a lossless channel. So, the entangled light beams are affected by the asymmetric optical loss. In this work we calculate the correlation variance of quadrature phase amplitudes of two-mode squeezed light under the asymmetric optical-loss conditions and discuss its non-classical correlation based on Duan’s and Simon’s inseparability criterion. The asymmetric optical loss sensitively increases the correlation variance and violates the inseparability criterion. In this work we consider asymmetric two-mode squeezed light as an initial state where the signal beam has larger quadrature phase amplitudes than the reference beam. After exposition to the asymmetric optical loss only the quadrature phase amplitudes of the signal beam is attenuated and become comparable to those of the reference beam. As a result it is expected that the asymmetric two-mode squeezed light has an ability to compensate the effect of the asymmetric optical loss and can maintain the inseparability criterion in the sense of Duan and Simon.
Two-mode squeezed light is an effective resource for quantum entanglement and shows a non-classical correlation between each optical mode. We are developing a two-mode squeezed light source to explore the possibility of quantum radar based on the quantum illumination theory. It is expected that the error probability for discrimination of target presence or absence is improved even in a lossy and noisy environment. We are also expecting to apply two-mode squeezed light source to quantum imaging. In this work we generated two-mode squeezed light and verify its quantum entanglement property towards quantum radar and imaging. Firstly we generated two independent single-mode squeezed light beams utilizing two sub-threshold optical parametric oscillators which include periodically-polled potassium titanyl phosphate crystals for the second order nonlinear interaction. Two single-mode squeezed light beams are combined using a half mirror with the relative optical phase of 90◦ between each optical field. Then entangled two-mode squeezed light beams can be generated. We observes correlation variances between quadrature phase amplitudes in entangled two-mode fields by balanced homodyne measurement. Finally we verified quantum entanglement property of two-mode squeezed light source based on Duan’s and Simon’s inseparability criterion.
Two-mode squeezed light is a macroscopic quantum entangled state of electro-magnetic fields and shows non-classical correlation between quadrature phase amplitudes in each optical mode. In this work the author is developing a high-quality two-mode squeezed light source for exploring the possibility of a quantum radar system based on a quantum illumination method and also expecting to apply it to quantum imaging. Two-mode squeezed light can be generated by combining two independent single-mode squeezed light beams using a beam splitter with a relative optical phase of 90 degrees between them. In current experimental progress the author developed two sub-threshold optical parametric oscillators to generate single-mode squeezed light beams. In the actual quantum radar or quantum imaging system, a turbulent atmosphere degrades quantum entanglement of a light source and affects performance of target detection. An optical loss is one of the simplest and most probable examples of environmental factors. In this work an evaluation method for quantum entanglement of two-mode squeezed light source is developed with consideration for the optical loss based on Duan's inseparability criteria.
Quantum illumination is a quantum sensing protocol primarily used for object detection, which aims to detect the presence of a target with low reflectivity in the free space using quantum light fields. Here we investigate a quantum illumination scheme using an entangled light source by performing non-Gaussian operations on the two-mode squeezed vacuum (TMSV) state in order to reduce the detection error probability and meanwhile improve the signal-to-noise (SNR) ratio. We demonstrate that under the same squeezing parameter, the non-Gaussian operations can significantly reduce the detection error rate compared with the original TMSV state. Under the same average signal photon number, both the TMSV states with and without non-Gaussian operations can provide smaller error rate than that of the coherent state. In addition, we consider the balanced homodyne detection on idler and return signal photons as joint measurement and find that non-Gaussian operations can enhance the SNR of target detection by about 6--9 dB compared with that using TMSV. These results here demonstrate the advantage of the non-Gaussian entangled source in quantum illumination protocol and can find potential applications in target detection in noisy environment.
Quantum illumination is a technique for detecting the presence of a target in a noisy environment by means of a quantum probe. We prove that the two-mode squeezed vacuum state is the optimal probe for quantum illumination in the scenario of asymmetric discrimination, where the goal is to minimize the decay rate of the probability of a false positive with a given probability of a false negative. Quantum illumination with two-mode squeezed vacuum states offers a 6 dB advantage in the error probability exponent compared to illumination with coherent states. Whether more advanced quantum illumination strategies may offer further improvements had been a longstanding open question. Our fundamental result proves that nothing can be gained by considering more exotic quantum states, such as, e.g., multimode entangled states. Our proof is based on a fundamental entropic inequality for the noisy quantum Gaussian attenuators. We also prove that without access to a quantum memory, the optimal probes for quantum illumination are the coherent states.
We started to research quantum illumination radar and quantum imaging by utilizing high quality continuous-wave two-mode squeezed light source as a quantum entanglement resource. Two-mode squeezed light is a macroscopic quantum entangled state of the electro-magnetic field and shows strong correlation between quadrature phase amplitudes of each optical field. One of the most effective methods to generate two-mode squeezed light is combining two independent single-mode squeezed lights by using a beam splitter with relative phase of 90 degrees between each optical field. As a first stage of our work we are developing two-mode squeezed light source for exploring the possibility of quantum illumination radar and quantum imaging. In this article we introduce current development of experimental investigation of single-mode squeezed light. We utilize a sub-threshold optical parametric oscillator with bow-tie configuration which includes a periodically-polled potassium titanyl phosphate crystal as a nonlinear optical medium. We observed the noise level of squeezed quadrature −3.08±0.13 dB and anti-squeezed quadrature at 9.29±0.13 dB, respectively. We also demonstrated the remote tuning of squeezing level of the light source which leads to the technology for tuning the quantum entanglement in order to adapt to the actual environmental condition.
Quantum illumination (QI) exploits quantum correlations to detect weakly reflecting targets embedded in noisy environments with higher sensitivity than classical illumination (CI). We investigate the effectiveness of QI in a realistic setting in which the signal sequentially interacts with a noisy environment and a lossy target. The target is considered at a temperature distinct from its surroundings, while both the interactions are modeled as an action of independent beam splitters with different reflectivities. The detection performance is quantified using the signal-to-noise ratio (SNR) and the quantum Chernoff bound (QCB), the latter providing an upper bound on the error probability. The performance of the Gaussian two-mode squeezed state (TMSS) is compared with that of the optimal classical protocol based on coherent states (CS). The proposed model shows that TMSS consistently achieves a higher SNR than CS for a low-reflectivity target and an arbitrary phase change and remains robust against thermal noise. Furthermore, a sufficiently lower QCB is obtained for TMSS than in previously reported results, indicating greater distinguishability between the presence and absence of the target. These findings underscore the role of realistic modeling in improving QI-based detection of lossy targets, with potential relevance to quantum radar and lidar systems.