Jianyu Wang

Chinese Academy of Sciences | CAS

Measurement-device-independent quantum key distribution (MDI QKD) provides immunity against all attacks targeting measurement devices. It is essential to implement MDI QKD in the future global-scale quantum communication network. Toward this goal, we demonstrate a robust MDI QKD fully covering daytime, overcoming the high background noise that prev...

Acousto-Optic Tunable Filter （AOTF） based spectroscopy instruments have been widely applied in biomedical， agricultural， aerospace， and other fields. However， the conventional AOTF spectrometers struggle to achieve increased system luminous flux while maintaining spectral resolution and reducing the number of samples. To address the above problems，...

The features of unmanned aerial vehicles (UAVs), such as strong manoeuvrability, small size, and light weight, make them considered to participate in free space optical (FSO) quantum communication, becoming an important part of the Space-Air-Ground Integrated Network. However, research reports on small-sized drones based long-range optical quantum...

Networks of optical clocks find applications in precise navigation1,2, in efforts to redefine the fundamental unit of the ‘second’3–6 and in gravitational tests7. As the frequency instability for state-of-the-art optical clocks has reached the 10−19 level8,9, the vision of a global-scale optical network that achieves comparable performances require...

The Lunar Mineralogical Spectrometer (LMS) is one of the main payloads on the Chang’E-5 (CE-5) lunar probe, belonging to the China Lunar Exploration Program. The scientific objective of the LMS is to explore the mineralogical composition and search for evidence of -OH/H 2 O in the sampling area. The LMS consists of an optomechanism unit, a dustproo...

Significant progress has been made in satellite-based quantum key distribution (QKD), and urgent follow-up work is to explore the optimal solution for building practical quantum constellations. Here, we demonstrate successful QKD based on the compact terminal on the Tiangong-2 Space Lab and construct a space–ground quantum network among four ground...

Quantum key distribution (QKD) uses the fundamental principles of quantum mechanics to share unconditionally secure keys between distant users. Previous works based on the quantum science satellite "Micius" have initially demonstrated the feasibility of a global QKD network. However, the practical applications of space-based QKD still face many tec...

Long-distance quantum state transfer (QST), which can be achieved with the help of quantum teleportation, is a core element of important quantum protocols. A typical situation for QST based on teleportation is one in which two remote communication partners (Alice and Bob) are far from the entanglement source (Charlie). Because of the atmospheric tu...

Near-infrared spectroscopy has been widely applied in various fields such as food analysis and agricultural testing. However, the conventional method of scanning the full spectrum of the sample and then invoking the model to analyze and predict results has a large amount of collected data, redundant information, slow acquisition speed, and high mod...

Optical clock networks play important roles in various fields, such as precise navigation, redefinition of "second" unit, and gravitational tests. To establish a global-scale optical clock network, it is essential to disseminate time and frequency with a stability of $10^{-19}$ over a long-distance free-space link. However, such attempts were limit...

Quantum interference plays an essential role in understanding the concepts of quantum physics. Moreover, the interference of photons is indispensable for large-scale quantum information processing. With the development of quantum networks, interference of photons transmitted through long-distance fiber channels has been widely implemented. However,...

DOI:https://doi.org/10.1103/PhysRevC.105.029903

In the experiment of quantum key distribution in free space, the polarization degradation and the propagation directions of the four polarization-encoded quantum light beams vary relative to each other and reduce the service life of the terminals, which severely limits their practical application. In order to solve the above problems, we report res...

Photon-counting detectors can increase the range of underwater optical wireless communication (UWOC) by enhancing the detection sensitivity and have thus become an active research area in recent years. However, system performance still needs to be improved in the reported underwater photon-counting communication (UPCC) experiments. In this study, a...

The Mars Mineralogical Spectrometer (MMS) is a hyperspectral imager onboard the Mars orbiter of Tianwen-1, China’s first Mars exploration mission. MMS consists of 4 subassemblies: an Optical Sensor Unit (OSU), an Electronics Unit (EU), a Calibration Unit (CU), and a Thermal Control Accessories (TCA). With a 0.5 mrad IFOV and a 416-sample cell array...

Microwave-based satellite–ground links are used to transfer time and frequency in various applications such as metrology, navigation, positioning, and very long baseline interferometers. The existing approaches, however, cannot fully satisfy the requirements of these applications. In this study, we investigated the possibility of an optical-based s...

Satellite angular micro-vibration has an important impact on the efficiency of space quantum communication links. We measured the micro-vibrations on the Micius satellite in orbit using a high-precision optical sensor mounted on the satellite and analyzed the power spectral density. We designed a compound axis acquisition, tracking, and pointing (A...

Quantum key distribution (QKD)1,2 has the potential to enable secure communication and information transfer³. In the laboratory, the feasibility of point-to-point QKD is evident from the early proof-of-concept demonstration in the laboratory over 32 centimetres⁴; this distance was later extended to the 100-kilometre scale5,6 with decoy-state QKD an...

Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted relays. Since the MDI-QKD protocol was proposed, fiber-based implementations aimed at longer distance, higher key rates, and network verification have been...

Satellite-based quantum communication is a promising approach for realizing global-scale quantum networks. For free-space quantum channel, single-mode fiber coupling is particularly important for improving signal-to-noise ratio of daylight quantum key distribution (QKD) and compatibility with standard fiber-based QKD. However, achieving a highly ef...

Satellite-based quantum communication is a promising approach for realizing global-scale quantum networks. For free-space quantum channel, single-mode fiber coupling is particularly important for improving the signal-to-noise ratio of daylight quantum key distribution (QKD) and compatibility with standard fiber-based QKD. However, achieving a highl...

Low probability subpixel target extraction and identification is important for hyperspectral (HS) applications. To better exploit the signatures of targets and extract targets from mixed pixels, we proposed a linear spectral unmixing algorithm combining HS and panchromatic (Pan) images (called SU-Co-Ims). However, misregistration between HS and Pan...

High-precision time synchronization for remote clocks plays an important role in fundamental science1–3 and real-life applications4,5. However, current time synchronization techniques6,7 have been shown to be vulnerable to sophisticated adversaries8. There is a compelling need for fundamentally new methods to distribute high-precision time informat...

Compared with hyperspectral remote sensing in visible-light, near infrared and short-wave infrared spectra, hyperspectral remote sensing in the thermal infrared spectrum has unique advantages, especially in the fields of mineral identification and pollution gas. At present, infrared hyperspectral imagers are rare and mainly airborne. In this paper,...

There are numerous algorithms that can be used to retrieve land surface temperature (LST) and land surface emissivity (LSE) from hyperspectral thermal infrared (HTIR) data. The algorithms are sensitive to a number of factors, where noise is difficult to handle due to its unpredictability. Although there is a lot of research regarding the influence...

Quantum key distribution (QKD)1,2,3 is a theoretically secure way of sharing secret keys between remote users. It has been demonstrated in a laboratory over a coiled optical fibre up to 404 kilometres long4,5,6,7. In the field, point-to-point QKD has been achieved from a satellite to a ground station up to 1,200 kilometres away8,9,10. However, real...

Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted relays. Since the MDI-QKD protocol was proposed, fibre-based implementations have been rapidly developed towards longer distance, higher key rates, and net...

High-precision time synchronization for remote clocks plays an important role in fundamental science and real-life applications. However, the current time synchronization techniques have been shown to be vulnerable to sophisticated adversaries. There is a compelling need for fundamentally new methods to distribute high-precision time information se...

We report the polarization preservation of quantum light in the optical systems of the terminals of the world's first quantum communication satellite, Micius. The main scientific experimental goals and polarization requirements of the satellite and ground station are introduced firstly. Three optical terminals are equipped on Micius to achieve our...

Time and frequency transfer lies at the heart of the field of metrology. Compared to current microwave dissemination such as GPS, optical domain dissemination can provide more than one order of magnitude in terms of higher accuracy, which allows for many applications such as the redefinition of the second, tests of general relativity and fundamenta...

High-fidelity transmission of polarization encoded qubits plays a key role in long distance quantum communication. By establishing the channel between ground and satellite, the communication distance can even exceed thousands of kilometers. Aimed to achieve the efficient uplink quantum communication, here we describe a high-fidelity polarization de...

Polarization maintenance is a key technology for free-space quantum communication. In this paper, we describe a polarization maintenance design of a transmitting antenna with an average polarization extinction ratio of 887 : 1 by a local test. We implemented a feasible polarization-compensation scheme for satellite motions that has a polarization f...

A low-divergence beam is an essential prerequisite for a high-efficiency longdistance optical link, particularly for satellite-based quantum communication. A point-ahead angle, caused by satellite motion, is always several times larger than the divergence angle of the signal beam. We design a novel transmitting antenna with a point-ahead function,...

Single-photon detectors (SPDs) play important roles in highly sensitive detection applications, such as fluorescence spectroscopy, remote sensing and ranging, deep space optical communications, elementary particle detection, and quantum communications. However, the adverse conditions in space, such as the increased radiation flux and thermal vacuum...

Polarization modulation plays a key role in polarization-encoding quantum key distribution (QKD). Here, we report a new, to the best of our knowledge, polarization modulation scheme based on an inherently stable Sagnac interferometer. The presented scheme is free of polarization mode dispersion and calibration as well as insensitive to environmenta...

Hyperspectral imaging technology has evolved for over thirty years and is widely used for geologic mapping, environmental monitoring, vegetation analysis, atmospheric characterization, biological and chemical detection, etc. With advances in technology, hyperspectral imagery not only determines the presence of materials and objects, but more import...

Single-photon detectors (SPDs) play important roles in highly sensitive detection applications, such as fluorescence spectroscopy, remote sensing and ranging, deep space optical communications, elementary particle detection, and quantum communications. However, the adverse conditions in space, such as the increased radiation flux and thermal vacuum...

Chang’e 4 is a robotic lunar exploration mission operated by the China National Space Administration and was to pull off the first-ever soft landing of space hardware on the mysterious lunar far side. The Visible and Near-IR Imaging Spectrometer (VNIS) is one of the main scientific instruments onboard the Chang’e 4 lunar rover. In order to analyze...

A test of quantum gravity Quantum mechanics and the general theory of relativity represent two pillars of modern physics, but unification of the two theories remains an open problem. Theories of quantum gravity abound, but they tend to lack an experimental foundation. One such proposed theory, event formalism, predicts that a pair of entangled part...

Quantum communication via seawater channels has attracted much attention. Here, we present the design and implementation of a prototype for space-to-underwater quantum key distribution (QKD). The influence of the fluctuating atmosphere–seawater interface is theoretically analyzed. The setup consists of a specially designed optical source working in...

We have focused on the optical form that is low cost while maintaining high performance for airborne application. We report the optical design as well as the alignment and test results for a push-broom imaging spectrometer. The smart architecture of the prism-grating based spectrometer ensures high uniformity and image quality. Moreover, an effecti...

The Chang’e-4 (CE-4) lunar rover, equipped with a visible and near-IR imaging spectrometer (VNIS) based on acousto-optic tunable filter spectroscopy, was launched to the far side of the moon on December 8, 2018. The detection band of the VNIS ranges from 0.45 to 2.4 μm. Because of the weak reflection of infrared radiation from the lunar surface, a...

The Chang’e-4 (CE-4) lunar rover, equipped with The Visible and Near-IR Imaging Spectrometer(VNIS) which based on acousto-optic tunable filter spectroscopy, was launched to the far side of the moon on December 8, 2018. The detection band of VNIS ranges from 0.45 to 2.4μm. Because of the weak reflection of infrared radiation from the lunar surface,...

The security of decoy-state quantum key distribution (QKD) highly depends on the accurate control of multiple intensity states. Although several theoretical studies on the QKD with loosely controlled source intensities have been proposed, there is still a large gap between the experimental realization and the theoretical analysis. In this paper, we...

Wide Swath and High Resolution Airborne Pushbroom Hyperspectral Imager (WiSHiRaPHI) is the new-generation airborne hyperspectral imager instrument of China, aimed at acquiring accurate spectral curve of target on the ground with both high spatial resolution and high spectral resolution. The spectral sampling interval of WiSHiRaPHI is 2.4 nm and the...

Shortwave infrared (SWIR) imaging technology attracts more and more attention by its fascinating ability of penetrating haze and smoke. For application of spaceborne remote sensing, spatial resolution of SWIR is lower compared with that of visible light (VIS) wavelength. It is difficult to balance between the spatial resolution and signal to noise...

Following calibration, hyperspectral images remain affected by spatial dimension nonuniformity, i.e., stripe noise, due to stray light interference, slit contamination, and instrument instability. The full spectrum airborne hyperspectral imager (FAHI) is a Chinese next-generation pushbroom sensor with a spectral range covering the visible near-infr...

The satellite-borne high-brightness source of polarization-entangled photons was developed and launched with the “Micius” quantum science satellite. With this source we implemented the Bell test between the satellite and the ground stations over 1200 km.

The quantum science satellite have been launched successfully in China. Utilizing this satellite, we have completed a series of quantum experiments in space. Here, I will introduce these experiments and our future plans.

Based on Micius satellite, we demonstrate two satellite-to-ground laser time transfer experiments with high repetition rate and high precision. It shows the feasibility to combine time transfer network with quantum communication network.

Mid-wave infrared hyperspectral imagers (MWHSIs) can be used to detect flames, high-temperature targets, and the radiance of Earth's surface. The acquired spectral signatures can be utilized to distinguish them even though the radiance are the same. In addition, in these applications, it is necessary to acquire the signatures of targets with suffic...

Free-space quantum key distribution (QKD) is important to realize a global-scale quantum communication network. However, performing QKD in daylight against the strong background light noise is a major challenge. Here, we develop the stochastic parallel gradient descent (SPGD) algorithm with a deformable mirror to improve the signal-to-noise ratio (...

A low-divergence beam is an essential prerequisite for a high-efficiency long-distance optical link, particularly for satellite-based quantum communication. A point-ahead angle, caused by satellite motion, is always several times larger than the divergence angle of the signal beam. We design a novel transmitting antenna with a point-ahead function,...

To establish optical links between an optical ground station (OGS) and a quantum experiment satellite, a method of acquisition for the Micius satellite is proposed in this paper and the acquisition technological specification of the OGS system is analyzed. An acquisition strategy for the OGS is designed to meet the requirements of the quantum exper...

Quantum entanglement was termed "spooky action at a distance" in the well-known paper by Einstein, Podolsky, and Rosen. Entanglement is expected to be distributed over longer and longer distances in both practical applications and fundamental research into the principles of nature. Here, we present a proposal for distributing entangled photon pairs...

We report on entanglement-based quantum key distribution between a low-Earth-orbit satellite equipped with a space borne entangled-photon source and a ground observatory. One of the entangled photons is measured locally at the satellite, and the other one is sent via a down link to the receiver in the Delingha ground station. The link attenuation i...

We studied the polarization evolution of a reflective telescope designed for the quantum satellite Micius. The change in polarization extinction ratio (PER) of quantum light was derived and calculated. The PER deterioration caused by increase of incidence angle was calculated to determine the boundary conditions for the system design. The performan...

We discuss and evaluate a long wave infrared imaging spectrometer in terms of its opto-mechanical design and analysis, alignment, testing, and calibration. The instrument is a practical airborne sensor achieving high spectral resolution and sensitive noise equivalent delta temperature. The instrument operates in the 8 to 12.5 µm spectral region wit...

The noise of fine tracking detectors in acquisition, tracking and pointing systems is different, which has different influences on the position location of light spots. The source of the strip noise of detectors is analyzed, and the influence of the strip noise on centroid algorithm is deduced theoretically. The threshold centroid algorithm is used...

Space-borne hyperspectral imagery is an important tool for earth sciences and industrial applications. Higher spatial and spectral resolutions have been sought persistently, although this results in more power, larger volume and weight during a space-borne spectral imager design. For miniaturization of hyperspectral imager and optimization of spect...

On the basis of presenting structure, control principle and control algorithm of acquisition, tracking and pointing (ATP) fine tracking subsystem, a semi physical model is built to analyze the tracking performance of digital to analog converters with different resolution, and tracking contrast experiments are carried out on the beams at the same po...

Quantum technology establishes a foundation for secure communication via quantum key distribution (QKD). In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satell...

Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. In practice, the achievable distance for QKD has been limited to a few hundred kilometers, due to the channel loss of fibers or terrestrial free space that exponentially reduced the p...

Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. In practice, the achievable distance for QKD has been limited to a few hundred kilometers, due to the channel loss of fibers or terrestrial free space that exponentially reduced the p...

In the past, long-distance free-space quantum communication experiments could only be implemented at night. During the daytime, the bright background sunlight prohibits quantum communication in transmission under conditions of high channel loss over long distances. Here, by choosing a working wavelength of 1,550 nm and developing free-space single-...

In practical applications, quantum systems work in a finite-temperature environment. Quantum entanglement is inevitably destroyed by the thermal noise. Here we experimentally demonstrate the protection of entanglement on the platform of linear optics. The finite-temperature thermal noise is described by the generalized amplitude-damping channel. By...

An arbitrary unknown quantum state cannot be precisely measured or perfectly replicated1. However, quantum teleportation allows faithful transfer of unknown quantum states from one object to another over long distance2, without physical travelling of the object itself. Long-distance teleportation has been recognized as a fundamental element in prot...

Infrared spectrum is very useful in the field of hyperspectral remote sensing. Because of the weak energy of infrared spectrum, the difficulty of the development of infrared focal plane, and the strong background, the development of the Infrared Hyperspectral Imaging System is very difficult. So far, the field is still in the laboratory research st...

Shortwave infrared (SWIR) imaging technology attracts more and more attention by its fascinating ability of penetrating haze and smoke. For application of spaceborne remote sensing, spatial resolution of SWIR is lower compared with that of visible light (VIS) wavelength. It is difficult to balance between the spatial resolution and signal to noise...

In the past, long-distance free-space quantum communication experiments could only be implemented at night. During the daytime, the bright background sunlight prohibits quantum communication in transmission under conditions of high channel loss over long distances. Here, by choosing a working wavelength of 1,550 nm and developing free-space single-...