Abstract: The invention is directed to a method of making ring laser resonator blocks according to the sandwich principle. Channel and hollow chamber structures are machined into two plates of a multiple expansion of a resonator block. The structures in the blocks complement each other. The plates machined in this manner are placed one atop the other and positioned in correspondence to the structures and joined to each other and thereafter separated into individual resonator blocks.

Abstract: An Nd:YAG laser of small size with a passive quality switch is combined with a slit-lamp instrument, to form an ophthalmological combination instrument for diagnosis and treatment. By a plurality of pulses within a pulse train, which succeed each other within the .mu. sec range, particularly good therapeutic effects are obtained. A second laser, emitting continuous visible radiation, has its beam aligned with the beam of invisible radiation from the first laser, and shows the user at all times the location of the beam of invisible radiation. The visible beam of radiation is split into two beams separated from each other by a light-free zone, and there is provision for blocking and unblocking these two beams alternately, which produces an effect which greatly aids the user in accurate focusing. This combination instrument affords the user the possibility of making a diagnosis and following it immediately by treatment.