Environmental CW range-resolved S-lidars with Si/InGaAs arrays: limitations and capabilities under sky background

Area of Science:

• Environmental Science
• Optical Engineering
• Remote Sensing Technology

Background:

• Open-path remote sensing instruments like S-lidars (Scheimpflug) are emerging for environmental monitoring.
• Skylight interference can degrade sensitivity and overload photodetectors in S-lidars, particularly in VIS and SWIR bands.
• Existing methods lack quantitative assessment of S-lidar performance under varying background illumination.

Purpose of the Study:

• To introduce a novel quantitative indicator, the index of immunity against external backgrounds, for S-lidars.
• To predict and analyze the limitations and potential of S-lidars in the presence of skylight.
• To provide a design rationale for enhancing S-lidar applicability in diverse environmental conditions.

Main Methods:

• Developed an index of immunity against external backgrounds by comparing signal-to-noise ratios with and without illumination.
• Normalized detector response to skylight for dimensionless estimates under variable conditions.
• Accounted for spectral and dark-current features of Si and InGaAs detectors under background illumination.

Main Results:

• Introduced a quantitative index for S-lidar immunity to background light.
• Demonstrated how to determine minimum array full well capacity to mitigate skylight effects.
• Provided a framework for stable S-lidar operation despite external illumination.

Conclusions:

• The proposed methodology enables the prediction of S-lidar performance under background illumination.
• The index of immunity is crucial for designing robust S-lidars for environmental monitoring.
• This work facilitates expanded applications of S-lidar technology in challenging lighting conditions.