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Upconversion-based Omnidirectional Laser Detector
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DOI：10.3788/gzxb20265505.0555211.png)
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Abstract
En 中文
The primary objective of this research is to develop a cost-effective, high-precision Short-Wave Infrared (SWIR) laser detection system that overcomes the financial and technical barriers inherent in traditional Indium Gallium Arsenide (InGaAs) sensor architectures. The study aims to demonstrate a novel technical pathway by integrating upconversion (UC) luminescence technology with mature, silicon-based visible-light Complementary Metal-Oxide-Semiconductor (CMOS) or Charge-Coupled Device (CCD) sensing platforms. This approach is specifically designed to target the 1 550 nm eye-safe laser wavelength, transforming it into detectable visible light to enable high-resolution imaging without the need for specialized infrared focal plane arrays. Furthermore, the research intends to realize wide-area omnidirectional detection capabilities by incorporating ultra-wide-angle optics and specialized computational rectification algorithms, thereby reconciling the long-standing conflict between wide-field coverage, high detection precision, and manufacturing affordability in contemporary optoelectronic systems. The methodology of this study involves the systematic integration of spectral conversion materials, wide-angle optical design, and digital signal processing. Initially, an up conversion thin-film layer was synthesized and applied as a spectral bridge, utilizing multi-photon absorption processes to convert 1 550 nm infrared photons into visible-light emissions tailored to the peak sensitivity range of a standard CMOS sensor. To achieve a near-hemispherical spatial coverage, a custom fish-eye lens assembly featuring a 170 degrees Field of View (FOV) was coupled to the sensing module. To address the significant radial and tangential geometric distortions induced by the fish-eye projection, a high-precision geometric distortion correction algorithm was implemented. This algorithm establishes a non-linear coordinate mapping model based on camera calibration parameters, allowing for the precise rectification of the captured imagery and the high-fidelity extraction of the laser spot's centroid. The system was then subjected to rigorous testing within a controlled optical laboratory environment, utilizing a 1 550 nm laser source mounted on a high-precision motorized rotation stage to evaluate angular precision, spatial resolution, and response uniformity across the entire detection hemisphere. The experimental evaluation reveals that the integrated detector system maintains exceptional performance metrics at the 1 550 nm operating wavelength. Data analysis indicates that the system achieves an angular detection precision of 0.17 degrees per pixel, demonstrating the effectiveness of the distortion correction algorithm in preserving spatial accuracy. On the image plane, the minimum resolvable focal spot radius was measured at 6 mu m, which closely aligns with the theoretical limits of the utilized CMOS sensor's pixel pitch, suggesting minimal loss of signal integrity during the spectral upconversion process. Furthermore, the system exhibited superior temporal response characteristics and spatial stability. Notably, across an extensive incident angle range of +/- 85 degrees -representing a near-complete hemispherical coverage-the response non-uniformity was recorded at less than 10%, indicating that the response uniformity exceeds 90% across the majority of the field of view. These quantitative results confirm that the upconversionbased sensing architecture provides reliable signal detection and localization even at extreme oblique angles of incidence.This research successfully validates the feasibility of utilizing upconversion technology as a highperformance alternative to traditional InGaAs-based short-wave infrared detection systems. The proposed architecture effectively bypasses the technical bottlenecks associated with shrinking pixel pitches and high fabrication costs of infrared semiconductor materials. By integrating wide-angle fish-eye optics with precise geometric rectification algorithms, the system provides a robust solution for omnidirectional laser sensing with high angular resolution. This approach establishes a transformative technical foundation for the development of next-generation, low-cost optoelectronic detection platforms, offering a scalable and efficient methodology for wide-area SWIR surveillance and laser-based navigation systems.
Keywords:
Upconversion technology
Laser detector
Fisheye lens
Distortion correction
Short-wave infrared