These are partial and complete laser rods of ruby. They were made in the Soviet Union and we got them from an old collection. These laser rods were meant for use in solid state lasers. They would have had light pumped into them from the side, either by a lamp or by another laser, absorbed that energy and converted it into the powerful coherent beam that lasers are known for. Ruby is the most classic laser crystal, having been at the heart of the very first laser in 1960. It is unfortunately rarely used now, but we acquired an old collection of soviet ruby laser rods from the Cold War era. These vary a lot in size, surface texture and preparation--each and every one is very cool!
