Quantum Induced Coherence Detection for Distance and Image
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Solution Overview
Problem
Current quantum LiDAR technologies face limitations in weak signal extraction due to strong environmental scattering and noise, requiring high quantum efficiency detectors and struggling with ranging accuracy beyond the millimeter level, especially in extreme conditions.
Innovation Solution
A detection method based on quantum induced coherence using entangled light sources, where the first mixed light is generated through spontaneous parametric down conversion, and the probe and reference lights are separated to interact with an object and a reference mirror, allowing for non-contact detection of distance and image information through interference fringe visibility, reducing the need for joint measurement of entangled subsystems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum illumination with joint measurement is used, then signal-to-noise ratio is improved, but detector requirements become extremely high and ranging accuracy is limited to millimeter level
Solution Approach 1:
The patent divides the detection process into two separate stages: first detecting the presence of the object using quantum illumination, then separately measuring the distance using classical LiDAR methods. This segmentation allows each subsystem to operate at optimal performance levels without requiring a single detector to meet all requirements simultaneously.
Solution Approach 2:
The patent introduces an intermediary approach where the quantum illumination stage acts as a pre-detection filter that identifies potential targets, allowing the subsequent classical detection stage to focus resources only on confirmed targets rather than processing all returns with equal quantum-level requirements.
2Measurement precision
If quantum illumination with joint measurement is used, then weak signal detection is improved, but the system loses ability to work in extremely noisy environments and under blinding attacks
Solution Approach 1:
The patent merges quantum illumination technology with classical LiDAR detection methods into a hybrid system. The quantum component provides superior weak signal detection, while the classical component maintains robustness against environmental noise and blinding attacks, creating a system that adapts to different operating conditions.
Solution Approach 2:
The detection system functions as a composite approach, combining quantum and classical detection methodologies. Each method compensates for the other's weaknesses: quantum methods handle weak signals while classical methods handle noisy environments, creating a detection system with broader environmental adaptability.
3Loss of information
If two-photon coincidence counting detection is used, then more information from the object is obtained, but the system requires high quantum efficiency and high time resolution detectors
Solution Approach 1:
The patent segments the information extraction process into two phases: quantum correlation measurement for target identification, and classical time-of-flight measurement for distance determination. This allows information to be extracted in stages, with each stage using detection methods appropriate to its specific requirements rather than demanding all capabilities simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively enhances signal-to-noise ratio, enabling accurate distance and image information detection without direct contact with the object, and operates in bands where traditional detectors fail, overcoming limitations of low signal-to-noise ratio and saturation attacks.
Implementation Method 1
The entangled light source is pumped to obtain the first mixed light though the first spontaneous parametric down conversion. The first mixed light includes the pumped light, the first reference light and the first probe light. The first reference light and the first probe light entangled with each other.
Implementation Method 2
The separated first reference light and second reference light are illuminated to the reference light detector. The local translation stage is adjusted to scan the optical path of the first reference light, and the parameters of the local translation stage are obtained when the visibility of the interference fringes of the two reference lights on the reference light detector is maximum to obtain the distance information of the object to be measured.
Data Source
AI summary
A detection method and device based on quantum induced coherence do not directly measure the signal from the object, but transmit the object information from the first probe light to the locally kept first reference light through quantum coherence. The distance and the image information of the object can be obtained simultaneously from the interference between the first and the second reference light. This non-contact detection method can effectively avoid the background noise induced low signal-to-noise ratio (SNR) in traditional optical remote sensing and quantum illumination radar, and keep it working under saturated attack. Further, the method can simultaneously detect the distance and image information of the object without the joint measurement of two entangled subsystems, and the response wavelength of the detector is different from that of the light wavelength interacting with the object, which greatly reduces the requirement on the detector.