Abstract: The present invention relates to a device for determining the position of a plurality of objects that are simultaneously trapped by a single laser beam, characterized in that the device comprises:—a laser source for emitting a laser beam, an actuation system for a three-dimensional deflecting of the laser beam between several trapping points,—a microscope objective for focusing the laser beam coming from the actuation system on the trapping points,—a sample chamber including the objects to be trapped on the trapping points,—a light source for lighten the sample chamber, and—a camera for determining the position of each of the trapped objects, said camera being located between the laser source and the actuation system, so that the light emitted by the light source passes successively through the sample chamber, the microscope objective, the actuation system and the camera.

Abstract: The present invention relates to a device (IO) for controlling the axial position of a laser focal point produced by a microscope objective, comprising: —a laser source for emitting a laser beam, —a deformable mirror for focusing or defocusing the laser beam axially, —a microscope objective for focusing the laser beam coming from the deformable mirror on a laser focal point, characterized in that it further comprises a system for passing the laser beam emitted by the laser source several times through the deformable mirror.