A method for optical pumping of particles and a device for implementing same. The particles (14) are changed from one long lifetime level to another long lifetime level via a short lifetime level by means of interaction with light radiation (16) emitted by a laser source. Prior to this interaction, the light radiation undergoes depolarization in a direction that is essentially perpendicular to the direction of propagation thereof, so as to reduce the entrapment of particles (14) in the black state.