In a groundbreaking development, a multi-institutional team of researchers has designed a single-photon time-of-flight LiDAR system capable of acquiring high-resolution 3D images of objects or scenes from distances as far as 1 kilometer. This innovation marks a significant leap forward in the capabilities of LiDAR (Light Detection and Ranging) technology, with potential applications in security, monitoring, and remote sensing. The system promises to offer detailed imaging even in challenging environmental conditions, such as when objects are obscured by foliage, camouflage netting, or smoke.
The LiDAR system leverages advanced single-photon detection technology and ultraprecise timing, enabling it to create sharp, clear 3D representations of distant targets with unparalleled spatial and depth resolution. According to Aongus McCarthy, a key member of the research team from Heriot-Watt University in the UK, the system achieves two critical breakthroughs: a detector twice as efficient as previous models and a timing resolution at least 10 times better than what has been reported by other groups working with similar LiDAR systems.
Key Features of the New LiDAR System
The system relies on an ultrasensitive single-photon detector known as the superconducting nanowire single-photon detector (SNSPD), developed through collaboration between researchers from MIT and NASA’s Jet Propulsion Laboratory (JPL). This specialized detector is capable of detecting individual photons of light, even at extremely low levels, making it possible to use eye-safe lasers with very low power to gather data over long distances. The SNSPD operates efficiently, detecting scattered light with exceptional precision.
To minimize noise and improve the quality of measurements, the SNSPD was cooled to just below 1 Kelvin, using a custom-built cryocooler system developed by the University of Glasgow team. This cooling ensures the detector remains sensitive to even the faintest light signals, improving the system’s performance in demanding conditions.
The researchers paired this high-performance detector with a custom single-pixel scanning transceiver that operates at a wavelength of 1550 nm—a wavelength commonly used in fiber-optic communications due to its favorable properties for long-range sensing. This combination of advanced hardware allows the system to take accurate time-of-flight measurements by timing how long it takes for a laser pulse to travel to an object and return, a technique that underpins most LiDAR systems.
Increased Precision and Higher Resolution
One of the major breakthroughs of this LiDAR system is its timing resolution. The system is capable of measuring time intervals with an accuracy of picoseconds (trillionths of a second), which enables it to distinguish depths as fine as 1 mm from distances of up to 325 meters. To put this into perspective, light travels about 300 millimeters in just 1,000 picoseconds. This precision allows the system to capture highly detailed 3D images, making it suitable for applications where clarity and resolution are paramount.
McCarthy and the research team emphasize that this enhanced depth resolution could dramatically improve imaging in situations where objects are hidden or partially obscured. For example, the system could penetrate camouflage netting or detect hidden objects behind foliage, which would be nearly impossible for conventional cameras to capture.
Field Testing and Demonstrations
The LiDAR system has undergone several field tests, including at Heriot-Watt University and in controlled environments to evaluate its performance. The tests involved measuring objects at distances of 45 meters, 325 meters, and 1 kilometer to evaluate both spatial resolution and depth accuracy. The researchers scanned custom 3D-printed targets with varying sizes and features to test the system’s ability to resolve intricate details.
At distances of 45 meters and 325 meters, the system was able to achieve depth resolution of up to 1 mm—approximately 10 times better than previous systems. This was a notable improvement, particularly in daylight conditions. During one of the tests, the system successfully captured a 3D image of a human face at 325 meters, demonstrating the system’s ability to acquire high-resolution data with an eye-safe laser and minimal processing.
These tests confirmed the system’s ability to detect and accurately map small features from long distances, with exceptional resolution. The 1 mm depth resolution is particularly useful in environments where precise measurements are needed, such as construction sites, environmental monitoring, or military operations.
Applications in Security, Monitoring, and Remote Sensing
The potential applications of this LiDAR system are vast. According to McCarthy, the system could lead to improved security and monitoring technologies. For example, it could be used to acquire detailed depth images through smoke, fog, or other atmospheric obscurants, which often hinder the effectiveness of traditional imaging systems. This could be a game-changer for search-and-rescue operations, where visibility is often compromised, or in surveillance scenarios where targets may be hidden behind physical barriers.
Another key application for this technology is in the remote identification of objects in various environments. The ability to capture detailed 3D images from kilometer-long distances means that this LiDAR system could be used to identify vehicles, infrastructure, and other objects, even in cluttered or obscured scenes. It could also be instrumental in monitoring natural disasters or environmental changes such as subsidence, providing real-time data that can help assess and mitigate potential hazards.
One of the most compelling uses of this technology is in defense and security, where being able to detect and visualize objects through camouflage or other concealing materials could be crucial. As McCarthy points out, the system’s ability to distinguish objects just a few centimeters behind obstacles, such as camouflage netting, could make a significant difference in military operations.
Future Directions and Further Developments
While the system has demonstrated remarkable performance in field trials up to 1 kilometer, the research team is already planning to test the system at even greater distances, including up to 10 kilometers. The team will also explore imaging in more challenging conditions, such as through atmospheric obscurants like smoke, fog, or rain, which often degrade the quality of traditional imaging systems.
Looking further ahead, the team envisions the potential for a mid-infrared LiDAR system that would operate at longer wavelengths than the current 1550 nm system. This could provide even better imaging through fog and other atmospheric disturbances, extending the system’s usefulness in a wider range of environments.
Additionally, the researchers are working on advanced computational methods to speed up the process of data analysis, which will be crucial for scaling the system to handle larger and more complex scenes. By improving the speed of image reconstruction and data processing, the system could be used for real-time applications, such as autonomous vehicles or dynamic surveillance systems.
Conclusion
The development of this high-resolution single-photon time-of-flight LiDAR system marks a significant advance in the field of remote sensing and imaging. By combining advanced photon detection, ultra-precise timing, and innovative system design, the researchers have created a system capable of capturing highly detailed 3D images from impressive distances. This technology has the potential to enhance a wide range of applications, from security and monitoring to environmental sensing and defense operations. As the research team continues to refine the system and test it in more challenging conditions, its future impact on both civilian and military technologies looks promising.
Reference: Aongus McCarthy et al, High-resolution long-distance depth imaging LiDAR with ultra-low timing jitter superconducting nanowire single-photon detectors, Optica (2025). DOI: 10.1364/OPTICA.544877