The invention relates to a particle detector including a substrate made of a semiconductor material, in which at least one through-cavity is formed, defined by an input section and an output section, wherein the input section thereof is to be connected to an airflow source, the substrate supporting: an optical means including at least one laser source, and at least one waveguide connected to the at least one laser source and leading into the vicinity of the output section of the cavity; and a photodetector located near the output section of the cavity and offset relative to the optical axis of the optical means.