Apparatus and method for applying a laser beam through a microscope

An inverted microscope is adapted so that a specimen thereon e.g. cells can be irradiated by a laser beam. The laser beam is guided from a laser source by a series of adjustably movable reflectors which introduce it into the microscope optical pathway at a parallel-beam region thereof, and through the objective lens of the microscope. A point to be irradiated can be selected by moving the reflectors which may be galvanometrically-movable. The laser beam can be focused together with the microscope image. The movable reflectors are kept within 200 mm behind the objective lens principal plane (PP) to ensure that the laser can be applied all over the microscope viewing field.