An improved laser pumping apparatus in which a plurality of generally spherical beads are disposed in pumping energy transmitting juxtaposition with the active outer surface of a laser element so as to be positioned between the active outer surface of the laser element and a pumping energy source. in a neodymium doped yttrium aluminum garnet laser element pumped by a flash lamp, the beads are made of silicon. The beads are approximately 50 to 100 microns in diameter and may be attached directly to the active outer surface of the laser element, such as by using a pumping energy transmitting adhesive, or the beads may be attached to an intermediate transparent or translucent pumping energy transmitting member such as a thin sleeve that fits over a laser element configured as a rod.

According to the invention, the metal vapor laser tube comprises a cylindrical plasma tube (1), which is located inside a leak-proof container (2) and which is surrounded by a thermal insulating material, an electrode (6) at each end of the plasma tube, and a cylindrical return conductor (9) coaxial to the plasma tube (1) which is connected with one of the electrodes, and characterized in that the return conductor (9) has a radius R of about: ##EQU1## where: e=exponential function, r=radius of the plasma tube, expressed in centimeters, dE/dV=energy density of the plasma, expressed in millijoules per cubic centimeter, ro=specific resistance of the plasma, expressed in Ohms.times.centimeter, U=electrical field, expressed in volts per centimeter.

A glass bead laser amplifier which is designed to operate efficiently at relatively high optical power outputs, and which is designed to be easily manufactured and scaled up in size to produce high power laser beams. The laser amplifier cavity if filled with doped glass lasing beads or elements which are packed therein to be in contiguous contact with each other. The shape of each glass element preferably provides a relatively large ratio of the external area to volume of the glass lasing element, to provide for efficient cooling thereof. A cooling system is provided for the laser amplifier cavity in which a coolant fluid circulates through the laser cavity around and between the contiguous glass lasing elements for cooling thereof. The cooling fluid is selected to have an index of refraction substantially matching that of the glass lasing elements to substantially reduce scattering of light passing through the glass/cooling fluid interfaces in the laser amplifier cavity. Moreover, a conjugate mirror is placed adjacent to one end of the laser amplifier cavity for reflecting the laser light which has passed once through the laser amplifier cavity back therethrough, to cancel the initial optical distortions introduced into the light beam as it initially passed through the laser amplifier cavity and the glass/cooling fluid interfaces therein. This results in the production of an output laser beam substantially unaffected by optical distortions which would otherwise be introduced by the laser amplifier.

A solid-state laser system for producing high output power and which is packaged in a small, cylindrical housing is set forth. The system includes a plurality of optical energy sources which emit energy that is absorbed by a solid-state laser medium that is configured as a rod. The solid-state laser medium has a central axis, first and second end surfaces, and outer surface between the end surfaces upon which the energy emitted from the optical energy sources is incident. The energy power sources are typically semiconductor laser diode arrays. The laser diode arrays are positioned adjacent to the cylindrical outer surface of the laser medium and usually extend along a substantial portion of the entire length of the outer surface. The system also includes first and second mirrors which are substantially aligned with the central axis of the laser medium for producing laser resonation through the first and second end surfaces of the laser medium. Because of the waste heat produced by the laser medium and the laser diode arrays, the laser system contains a manifold system for circulating a fluid past these components. The cylindrical housing has a diameter that is preferably less than about 2.0 inches and is mechanically coupled to the optics bench. The cylindrical housing is the same size as the housings used in other low-power laser systems so that the same mounting structures which are commonly used to support these other common lasers can be used to support this high-power, solid-state laser system.

A housing for a slab laser gain media with a rectangular cross section which provides for a uniform flow of coolant over the slab top and bottom surfaces (18) and (20), while insulating the slab side surfaces (14) and (16). The slab gain media is bonded between two tabs at each end of the housing (48a, 48b, 50a, 50b). The slab top and bottom surfaces are made level with the tab top and bottom surfaces. Seals are placed on the continuous surface formed by the slab top and bottom surfaces and the tab top and bottom surfaces, thus sealing the ends of the housing, and also surrounding the coolant inlets and outlets. Windows (32) and (34) are then placed on top of each seal to form two thin cavities confining the coolant to flow across the slab top and bottom surfaces (18) and (20), and allowing for the close-coupling of either one or two pump sources, such as a two dimensional laser diode array assembly (58) and (60).