Laser Wavelength Detection via Dual-Sensor Ratio Analysis
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Solution Overview
Problem
Conventional laser detection systems are inadequate for reliably identifying and distinguishing between different wavelengths of laser radiation, particularly in aircraft and military contexts, where accurate detection is critical for pilot safety and mission success.
Innovation Solution
A laser wavelength detector system comprising first and second sensors with a common field of view, where a filter with varying monochromatic attenuation coefficients optically couples the second sensor, allowing for identification of laser wavelengths based on the intensity ratio between the two sensors, and a control module determines the wavelength using a lookup table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laser detection systems are used, then laser radiation can be detected, but wavelength identification and discrimination are unreliable
Solution Approach 1:
The system divides the detection function into multiple sensors (first sensor and second sensor) with different spectral responses. Each sensor detects the same laser radiation but with different attenuation characteristics, allowing wavelength discrimination through ratio comparison of their outputs.
Solution Approach 2:
The filter's monochromatic attenuation coefficient varies with wavelength, creating wavelength-dependent attenuation. By measuring the ratio of sensor outputs and comparing it to the known filter attenuation characteristics at different wavelengths, the system identifies the laser wavelength.
2Measurement precision
If a filter with varying attenuation coefficients is used, then wavelength discrimination is enabled, but device complexity increases
Solution Approach 1:
The filter acts as an intermediary element between the laser radiation and the second sensor. It modifies the radiation in a wavelength-dependent manner, encoding wavelength information into the attenuation pattern that can be decoded by comparing sensor ratios.
Solution Approach 2:
The system uses two sensors to create duplicate measurements of the same laser signal, but with different attenuation characteristics. By comparing these copies, the system extracts wavelength information without requiring complex spectral analysis equipment.
3Measurement precision
If multiple sensors with different spectral responses are used, then wavelength identification is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The system deliberately uses sensors with different spectral response parameters (different sensitivity curves) rather than requiring matched sensors. The filter's wavelength-dependent attenuation compensates for sensor variations, and the ratio measurement approach eliminates the need for precise sensor matching.
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
The system effectively discriminates between different laser wavelengths, enhancing pilot safety and military operations by providing accurate identification and countermeasures, even in the presence of a solar background, and reducing costs through the use of PIN photodetectors.
Implementation Method 1
A filter having two or more monochromatic attenuation coefficients optically couples the second sensor to the field of view. The filter attenuates incident monochromatic laser illumination of a first wavelength more heavily than incident monochromatic laser illumination of a second wavelength
Implementation Method 2
Either or both of the first sensor and the second can include a PIN photodetector
Data Source
AI summary
A laser wavelength detector includes first and second sensors having a common field of view. A filter having two or more monochromatic attenuation coefficients optically couples the second sensor to the field of view. The filter attenuates incident monochromatic laser illumination detected by the second sensor more heavily than incident monochromatic laser illumination detected by the first sensor such that wavelength of incident laser illumination can be identified according to a ratio of first and second sensor intensities.