Multi-Wavelength Laser Detection System with Telescopic Optics
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Solution Overview
Problem
Current Raman spectroscopy systems face challenges in achieving efficient stand-off distance detection of chemicals and explosives beyond 1.5 meters, with limitations in multi-wavelength capabilities and interference from luminescence or fluorescence bands, which hinders accurate and efficient detection at longer ranges.
Innovation Solution
A multi-wavelength laser system capable of producing output wavelengths from deep UV to near IR, integrated with high power Nd:YAG fiber lasers and telescopic optics, allowing for the detection of trace elements indicating explosives at distances up to or greater than 40 meters, and incorporating dichroic splitter carousels and variable beam expander/diverger optics to minimize interference and maximize detection range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-wavelength laser system is used for Raman detection, then the system structure is simple, but the detection range and versatility are limited
Solution Approach 1:
The patent implements a multi-wavelength laser system where a single laser source can operate at multiple wavelengths (532nm, 638nm, 785nm, 1064nm) through wavelength selection mechanisms. This allows the same detection system to analyze different chemical substances that require specific excitation wavelengths, eliminating the need for multiple separate single-wavelength systems and thereby improving versatility without proportionally increasing complexity.
Solution Approach 2:
The system incorporates dynamic wavelength selection capability where the laser can switch between different wavelengths based on detection requirements. This dynamic adaptability allows the system to optimize performance for different chemical analyses while maintaining a unified platform, resolving the contradiction between versatility and complexity.
2Length of stationary object
If detection is performed at close range (within 1.5 meters), then signal strength is sufficient, but the system cannot achieve stand-off distance detection
Solution Approach 1:
The patent employs multiple laser wavelengths (532nm, 638nm, 785nm, 1064nm) to optimize detection at different distances. By selecting appropriate wavelengths based on atmospheric transmission characteristics and target properties, the system extends effective detection distance while maintaining signal quality and measurement precision through parameter optimization.
3Measurement precision
If luminescence or fluorescence bands are present in the detection path, then additional signal information is obtained, but interference with Raman signal detection occurs
Solution Approach 1:
The patent utilizes dichroic splitter carousels to separate different wavelength components of the collected light. This extraction mechanism isolates the Raman signal from luminescence and fluorescence interference by directing different wavelength ranges to appropriate detectors, thereby removing harmful interference while preserving useful signal information.
Solution Approach 2:
The system introduces wavelength-selective optical elements (dichroic mirrors, filters) as intermediaries between the sample and detector. These intermediaries selectively transmit or reflect specific wavelength ranges, allowing the Raman signal to be isolated from overlapping luminescence and fluorescence bands, thus resolving the interference problem.
Data Source
AI summary
A system comprises a processing system, a laser system, a telescope system, a detector system and optical systems operatively arranged such that the laser system may be capable of outputting multiple wavelengths to a common telescope system, and the detector system is capable of receiving signatures from the same telescope system, under the control of a control system. The processor system processes signals received from the detector system to determine substances identified by known signatures. For example, a plurality of detectors in the detector system each receive a range of wavelengths of the signatures received by the telescope system. For example, a variable beam diverger and variable beam expander operatively control expansion and divergence of the output the laser system. For example, a beam reducer and lenslet array may operatively transmit signatures via optical fiber bundle to one or more of the detectors.