Dust optical concentration measuring method, involves determining concentration of component such as dust, from transmission and optical path length, where optical path length is measured by determining delay of laser pulse

摘要

The method involves guiding radiation of a distributed feedback (DFB)-diode laser (10) through a measuring volume on a retro-reflector (14). The radiation at the reflector is reflected back through the measuring volume to a radiation detector (16). An optical power or intensity or energy is measured, and the concentration of the component such as dust, is determined from a transmission and optical path length, where the optical path length is measured under application of same component by determining delay of a laser pulse.