We report a proof-of-principle experimental demonstration of a turbulence-resistant quantum Lidar system. As a key technology for sensing and ranging, Lidar has drawn considerable attention for a study from quantum perspective, in search of proven advantages complementary to the capabilities of conventional Lidar technologies. Environmental factors such as strong atmospheric turbulence can have detrimental effects on the performance of these systems. We demonstrate the possibility of turbulence-resistant operation of a quantum Lidar system via two-photon interference of entangled photon pairs. Additionally, the reported quantum Lidar also demonstrates the expected noise resistance. This study suggests a potential high precision timing-positioning technology operable under turbulence and noise.
We report a proof-of-principle experimental demonstration of a turbulence-resistant quantum Lidar system. As a key technology for sensing and ranging, Lidar has drawn considerable attention for a study from quantum perspective, in search of proven advantages complementary to the capabilities of conventional Lidar technologies. Environmental factors such as strong atmospheric turbulence can have detrimental effects on the performance of these systems. We demonstrate the possibility of turbulence-resistant operation of a quantum Lidar system via two-photon interference of entangled photon pairs. Additionally, the reported quantum Lidar also demonstrates the expected noise resistance. This study suggests a potential high precision timing-positioning technology operable under turbulence and noise.
Quantum light detection and ranging (LiDAR) utilizes quantum entanglement and correlation to improve precision, noise resilience and covertness of target detection. Despite recent advances, the development of a quantum LiDAR system that simultaneously achieves high precision and a large measurement range remains challenging. Here, we demonstrate a quantum amplitude-modulated continuous wave LiDAR with micrometer precision achievable via increased acquisition time and meter-scale measurement range. In our demonstration, the signal photons directly illuminate the target, while the idler photons are non-locally modulated with a high-frequency cosine wave and never interact with the target. By leveraging the non-local modulation and the quantum correlation, the target detection is achieved with a precision of 0.64 ± 0.06 mm within one second over a measurement range of 2-8 m. As the acquisition time is up to 500 s, the system achieves a precision of 29 ±4μm. Furthermore, our system realizes a 50 times precision improvement over the classical single-photon scheme in a background noise 37 dB stronger than the returned probe photons. With these advantages, our method will open venues for the development of high-precision, long-range, and noise-resilient target detection.
Modern optical sensing systems, particularly LiDAR, play a central role in remote sensing and precision measurement. However, they face fundamental limits when operating in noisy and highly lossy environments. Quantum illumination has emerged as a promising approach to overcome these challenges by exploiting quantum correlations. This work presents the system design and performance analysis of a quantum illumination based LiDAR architecture operating at optical frequencies. The proposed system exploits entangled photon pairs generated through spontaneous parametric down conversion to enhance detection sensitivity and robustness under weak return conditions. A complete hardware oriented framework is developed, including the entanglement source, nonlinear crystal configuration, pump laser requirements, optical propagation path, quantum memory implementation, and a detection architecture based on quantum erasure Hong-Ou-Mandel interference. Practical realization using superconducting nanowire single photon detectors is discussed to enable high efficiency and low noise photon measurement. In addition, a system level link budget and noise analysis evaluates the impact of optical losses, atmospheric attenuation, turbulence, and detector imperfections on overall performance. The study highlights how quantum correlations can improve signal to noise performance compared with classical illumination strategies, particularly in low reflectivity and high background scenarios. The presented architecture provides a realistic framework for implementing quantum LiDAR systems and supports the development of next generation long range sensing technologies.
The counterintuitive emergence of second-order interference beyond the coherence length has been observed and reported in quantum optical systems [1], [2]. This phenomenon can lead to potential remote sensing applications by overcoming the key limitation of the coherent LIDAR (Light Detection and Ranging), such as the source coherence length, which defines the maximum detection range. In this work, we present an experimental demonstration of coherent two-photon LIDAR beyond the coherence length with thermal light.
Entanglement and correlation of quantum light can enhance LiDAR sensitivity in the presence of strong background noise. However, the power of such quantum sources is fundamentally limited to a stream of single photons and cannot compete with the detection range of high-power classical LiDAR transmitters. To circumvent this, we develop and demonstrate a quantum-inspired LiDAR prototype based on coherent measurement of classical time-frequency correlations. This system uses a high-power classical source and maintains the high noise rejection advantage of quantum LiDARs. In particular, we show that it can achieve over 100dB rejection (with 100ms integration time) of indistinguishable(with statistically identical properties in every degrees of freedom) in-band noise while still being sensitive to single photon signals. In addition to the LiDAR demonstration, we also discuss the potential of the proposed LiDAR receiver for quantum information applications. In particular, we propose the chaotic quantum frequency conversion technique for coherent manipulation of high dimensional quantum states of light. It is shown that this technique can provide improved performance in terms of selectivity and efficiency as compared to pulse-based quantum frequency conversion.
In this invited paper we review our recent research activities on experimental demonstration of entanglement based (EB) radars, operated over strong atmospheric turbulence channels. In conventional EB communications, sensing, and radars the phase-conjugation, required before homodyne detection takes place, is performed on received signal photons. In atmospheric turbulent channels, the signal photons are affected by diffraction, absorption, scattering, and atmospheric turbulence effects so that only limited number of weak target probe returned signal photons reach the receiver side in EB radars. Moreover, it is extremely difficult to perform any phase-conjugation on weak signal photons when the average number of received photons is <<1. To solve this problem, we have recently proposed to perform phase-conjugation on bright idler photons instead. Namely, we perform the wavelength conversion by the PPLN waveguide on bright idler photons, so that the idler photons will have the same wavelength as the signal photons, and after that we use a classical homodyne balanced detector as an entanglement assisted detector. To generate entangled photon pairs, we use C-/L-band tunable laser, EDFA, the PPLN waveguide, and WDM demultiplexers. To demonstrate the high-potential of the proposed EB radar concept, we developed an experimental outdoor free-space optical (FSO) testbed at the University of Arizona campus. Using this FSO testbed we experimentally demonstrate that the proposed EB radar significantly outperforms the corresponding classical counterpart and can operate in strong turbulence regime. To improve the detection probabilities further, we use deformable mirror-based adaptive optics.