An optical arrangement, in particular a laser scanning microscope, having a light source, in particular a laser light source, and an interruption device (1) for a light beam (2) of the light source, is configured, in the interest of reliable operation, in such a way that means (3) for monitoring the functioning of the interruption device (1) are associated with the interruption device (1). The invention additionally concerns a shutter (5) for a light beam (2) of a light source, in particular a laser light source, which, again in the interest of reliable operation of an optical arrangement, is characterized by at least two movable components (6, 7) which are configured and arranged such that the mechanical momentum generated by a moving component (6) or by several moving components is compensated for by the motion of the other component (7) or components.