A radio-frequency excited carbon dioxide (CO.sub.2) or carbon monoxide (CO) gas laser includes two electrodes, which have passivated surfaces, within a sealed housing. Features in a ceramic slab or a ceramic cylinder located between the electrodes define a gain volume. Surfaces of the ceramic slab or the ceramic cylinder are separated from the passivated surfaces of the electrodes by small gaps to prevent abrasion thereof. Reducing compressive forces that secure these components within the housing further reduces abrasion, thereby extending the operational lifetime of the gas laser.

A radio-frequency excited carbon dioxide (CO.sub.2) or carbon monoxide (CO) gas laser includes two electrodes, which have passivated surfaces, within a sealed housing. Features in a ceramic slab or a ceramic cylinder located between the electrodes define a gain volume. Surfaces of the ceramic slab or the ceramic cylinder are separated from the passivated surfaces of the electrodes by small gaps to prevent abrasion thereof. Reducing compressive forces that secure these components within the housing further reduces abrasion, thereby extending the operational lifetime of the gas laser.

A multi-pass coaxial molecular gas laser is described in both symmetrical and asymmetrical configuration. An anode vessel receives lasing gas and the gas flows through one or more plasma channels to a cathode vessel which receives the gas and redirects it in the closed system. A second anode vessel may alternatively be provided to double length of the plasma channel and increase surface area exposure of the optical beam to the energized gas. Non-laminar gas flow may be created using spiral nozzles at the entrance of the optical resonator.

A multi-pass coaxial molecular gas laser is described in both symmetrical and asymmetrical configuration. An anode vessel receives lasing gas and the gas flows through one or more plasma channels to a cathode vessel which receives the gas and redirects it in the closed system. A second anode vessel may alternatively be provided to double length of the plasma channel and increase surface area exposure of the optical beam to the energized gas. Non-laminar gas flow may be created using spiral nozzles at the entrance of the optical resonator.

A light source apparatus includes a gas discharge stage including a three-dimensional body defining a cavity that is configured to interact with an energy source, the body including at least two ports that are transmissive to a light beam having a wavelength in the ultraviolet range; a sensor system comprising a plurality of sensors, each sensor is configured to measure a physical aspect of a respective distinct region of the body of the gas discharge stage relative to that sensor; and a control apparatus in communication with the sensor system. The control apparatus is configured to analyze the measured physical aspects from the sensors to thereby determine a position of the body of the gas discharge stage in an XYZ coordinate system defined by an X axis, wherein the X axis is defined by the geometry of the gas discharge stage.

A light source apparatus includes an airtight container having a hemispherical or semielliptical first curved portion configured to receive laser light, a hemispherical or semielliptical second curved portion opposite to the first curved portion, and a cylindrical portion connecting the first curved portion and the second curved portion; assist gas sealed in the airtight container; and a light source configured to irradiate laser light to the first curved portion from outside of the airtight container.

A radio-frequency excited carbon dioxide (CO.sub.2) or carbon monoxide (CO) gas laser includes two electrodes, which have passivated surfaces, within a sealed housing. Features in a ceramic slab or a ceramic cylinder located between the electrodes define a gain volume. Surfaces of the ceramic slab or the ceramic cylinder are separated from the passivated surfaces of the electrodes by small gaps to prevent abrasion thereof. Reducing compressive forces that secure these components within the housing further reduces abrasion, thereby extending the operational lifetime of the gas laser.

A compact laser system with a folded annular resonator cavity defined by spherical mirrors (17, 18), enabling the generation of a multipass beam path between the mirrors, each beam pass inclined at a small angle to the axis between the mirrors to form a zig-zag path (28, 29) therebetween. A long optical path is achieved within a short physical structure. The optical resonator cavity is confined in the gap between two cylindrical coaxial electrodes (13, 14) receiving RF power to excite the lasing gas. Apertures (23) are provided in the main cavity mirrors (17, 18), with a high reflectivity end mirror (24) behind one aperture at one end and a partially reflective output coupler (25) at the other end. A channeled ceramic cylindrical element (15, 20) within the annular shaped gap between the two cylindrical electrodes confines the lasing gas to the channels (16).

The present disclosure relates, generally, to lasers and, more particularly, to lasers with a setback aperture. In one in illustrative embodiment, a laser comprises front and rear resonator mirrors, an output window positioned near the front resonator mirror, and a plurality of waveguide walls extending between the front and rear resonator mirrors and extending between the rear resonator mirror and an aperture defined by the plurality of waveguide walls, such that a laser beam formed between the front and rear resonator mirrors will propagate in free-space between the aperture and the output window so that a first cross-sectional profile of the laser beam at the aperture will be different than a second cross-sectional profile of the laser beam at the output window.

A radio-frequency, RF, slab laser 10 with a Z-fold resonator cavity defined by an output mirror 32, a first fold mirror 34, a second fold mirror 36 and a rear mirror 30. The second fold mirror 36 is rotated by an adjustment angle away from the angle it would have if the mirrors were all plane mirrors and directed the round trip beam path by direct reflection. Moreover, the rear mirror 30 is rotated by an adjustment angle that is approximately twice the adjustment angle of the second fold mirror 36. These rotations of the rear mirror 30 and second fold mirror 36 suppresses parasitic mode paths that would otherwise exist.