Device comprising: - a frame - injection means (203.2), arranged for injecting a light beam into the device, - an immersion chamber, - guiding means (203.1) arranged for guiding the light beam from the injection means (203.2) and into the immersion chamber along an optical guide path, and - shaping means (302, 303, 305), arranged for shaping the light beam originating from the injection means (203.2) so as to give it a shape that is elongated in one spatial dimension so as to create a light sheet in a sheet plane situated in the immersion chamber, - an objective, an observation plane of which is situated in the immersion chamber and is perpendicular to an optical axis of the objective, said objective comprising a distal end orientated towards the immersion chamber and a proximal end, the immersion chamber comprising: - an aperture which is hole arranged in order to allow passage of a sample, and - a bottom, the distal end of the objective being situated on the side of the bottom of the immersion chamber so that the aperture of the immersion chamber, the sheet plane and the distal end of the objective are aligned in this order characterized in that the shaping means (302, 303, 305): - form part of the guiding means (203.1) and are situated along the optical guide path between the injection means (203.2) and the immersion chamber, - are situated between a first plane perpendicular to the optical axis of the objective and passing through the aperture of the immersion chamber and a second plane, this second plane: • being perpendicular to the optical axis of the objective and • being situated beyond the distal end of the objective with respect to the first plane and • intersecting the device at a fastening means arranged for fastening the device by optically connecting the objective to an objective holder of the microscope the injection means (203.2), the objective, the immersion chamber, the guiding means (203.1) and the shaping means (302, 303, 305) being secured together within the frame. - a frame - injection means (203.2), arranged for injecting a light beam into the device, - an immersion chamber, - guiding means (203.1) arranged for guiding the light beam from the injection means (203.2) and into the immersion chamber along an optical guide path, and - shaping means (302, 303, 305), arranged for shaping the light beam originating from the injection means (203.2) so as to give it a shape that is elongated in one spatial dimension so as to create a light sheet in a sheet plane situated in the immersion chamber, - an objective, an observation plane of which is situated in the immersion chamber and is perpendicular to an optical axis of the objective, said objective comprising a distal end orientated towards the immersion chamber and a proximal end, - an aperture which is hole arranged in order to allow passage of a sample, and - a bottom, - form part of the guiding means (203.1) and are situated along the optical guide path between the injection means (203.2) and the immersion chamber, - are situated between a first plane perpendicular to the optical axis of the objective and passing through the aperture of the immersion chamber and a second plane, this second plane: • being perpendicular to the optical axis of the objective and • being situated beyond the distal end of the objective with respect to the first plane and • intersecting the device at a fastening means arranged for fastening the device by optically connecting the objective to an objective holder of the microscope the injection means (203.2), the objective, the immersion chamber, the guiding means (203.1) and the shaping means (302, 303, 305) being secured together within the frame. • being perpendicular to the optical axis of the objective and • being situated beyond the distal end of the objective with respect to the first plane and • intersecting the device at a fastening means arranged for fastening the device by optically connecting the objective to an objective holder of the microscope