The invention relates to a particle detector including a substrate (10, 30, 40) made of a semiconductor material, in which at least one through-cavity (11, 31, 41) is formed, defined by an input section (110) and an output section (111), wherein the input section thereof is to be connected to an airflow source, said substrate supporting: an optical means including at least one laser source (12, 32, 42), and at least one waveguide (13, 33, 43) connected to said at least one laser source and leading into the vicinity of the output section of said cavity; and photodetector means (14, 34, 44) located near the output section of said cavity and offset relative to the optical axis of the optical means.