Open-Path Gas Detection With Multi-Wavelength Spectroscopy

The patent segments the broadband radiation spectrum into multiple discrete wavelength channels using a diffraction grating and array detector. Instead of using a beam splitter with limited two-channel capability, the system divides the spectrum into many wavelength bands, allowing selective measurement at multiple signal and reference wavelengths simultaneously. This segmentation enables discrimination between gas absorption signatures and environmental interference patterns.

The patent transitions from a limited two-channel detection approach to a multi-dimensional spectral analysis by measuring radiation intensity across many wavelength channels simultaneously. This dimensional expansion in the spectral domain allows the system to identify gas-specific absorption patterns and distinguish them from broad-spectrum environmental effects like scattering and obscuration.

The patent employs a universal diffraction grating that can disperse broadband radiation into multiple wavelength channels simultaneously, making the single optical path capable of serving multiple detection functions. The array detector further enhances this universality by providing multiple sensing elements that can detect different wavelength bands concurrently, eliminating the need for multiple separate detection paths and enabling versatile multi-gas detection capability.

The patent replaces the mechanical beam splitter system with an optical diffraction-based system. Instead of using physical beam splitting and multiple bandpass filters, the system uses a diffraction grating to spatially separate wavelengths and an array detector to simultaneously measure multiple channels. This substitution eliminates the mechanical limitations of beam splitters and enables unlimited wavelength channel detection.