Patent ID: 8390791

Claim:
A method of light detection comprising: emitting a pulsed light beam from a pulsed light source; splitting the pulsed light beam with a beam splitting device into a first light beam ray set having a first detection range and a second light beam ray set having a second detection range, wherein the first detection range is selected to aim the first light beam ray set to a first portion of airborne particulates at a first distance from the beam splitting device, wherein the second detection range is selected to aim the second light beam ray set to a second portion of the airborne particulates at a second distance from the beam splitting device, the second distance being lesser than the first distance; at least one of the first light beam ray set and the second light beam ray set colliding with airborne particulates, thereby resulting in backscattered light; receiving the backscattered light through at least one aperture; and detecting the received backscattered light at a detector.