Systems and methods in which multi-dimensional metric monitoring is used with respect to multi-wavelength scattering for smoke detection are described. A multi-dimensional metric may dynamically track a slope of a relationship between scattered light of multiple wavelengths of scattered light being monitored. A multi-dimensional metric monitoring smoke detection algorithm may utilize multi-dimensional thresholds with respect to monitoring of the multi-dimensional metric for initiating a fire alarm and resetting the fire alarm. An optical measuring chamber utilized for providing multi-wavelength scattering signals utilized in deriving a multi-dimensional metric for smoke detection may be configured for wide-scattering-angle signal collection, such as using a light trapping sub-chamber having a light-guide diaphragm assembly configured for wide-scattering-angle signal collection.