Discharge electrodes include a cathode and an anode. The anode is disposed to face the cathode in a discharge direction perpendicular to a longitudinal direction of the cathode, and includes an electrode base 1, and a coating layer that covers a portion of a surface of the electrode base. First corners in a cross section perpendicular to the longitudinal direction connect first straight sections formed of first side surfaces that are side surfaces of the electrode base to a first curved section formed of a first discharge surface that is a discharge surface of the electrode base. The first corners are closer to the cathode in the discharge direction than second corners connecting second straight sections formed of second side surfaces that are side surfaces of the coating layer to a second curved section formed of a second discharge surface that is a discharge surface of the coating layer.

A carbon dioxide gas-discharge slab-laser is assembled in a laser-housing. The laser-housing is formed from a hollow extrusion. An interior surface of the extrusion provides a ground electrode of the laser. Another live electrode is located within the extrusion, electrically insulated from and parallel to the ground electrode, forming a discharge-gap of the slab-laser. The electrodes are spaced apart by parallel ceramic strips. Neither the extrusion, nor the live electrode, include fluid coolant channels. The laser-housing is cooled by fluid-cooled plates attached to the outside thereof.

A gas laser apparatus may include a chamber filled with a laser gas; a window provided in the chamber and through which a laser beam passes; an optical path tube connected to the chamber to surround a position of the window in the chamber; a heated gas supply port configured to supply a heated purge gas into a closed space including a space in the optical path tube; and an exhaust port configured to exhaust a gas in the closed space.

Disclosed is an exchangeable laser unit and an array thereof. The exchangeable laser unit includes cartridge receivers and housings having a uniform shape and uniform optical interfaces. The cartridge receiver adopts the optical interface including a tapered cavity and cylindrical cavity, so that a precise mechanical connection can be achieved between the output of laser of the cartridge receiver and the output of the optical fiber of the housing without professional tools, facilitating standardization of the output components of the laser elements of the cartridge receiver. In addition, the upper-lower guide rails and the upper-lower channels having certain of inclination degree can realize the precise positioning of the cartridge receiver and the housing. When replacing one laser element by a laser element that emits laser with a different wavelength, it is only necessary to replace the cartridge receiver inside the housing. That is, the replacement of laser elements having different wavelengths is converted to the replacement of cartridge receivers, which greatly reduces the difficulty for medical personnel to switch laser wavelengths, and improves the popularization of laser therapeutic instruments in the medical field. In the exchangeable laser array of the disclosure, the cartridge receiver inside the housing can be replaced by other cartridge receiver that emits laser with a different wavelength, and the plurality of housings can be connected with a plurality of wavelength switchers in the back to realize selective output of the wavelength.

Disclosed is an exchangeable laser unit and an array thereof. The exchangeable laser unit includes cartridge receivers and housings having a uniform shape and uniform optical interfaces. The cartridge receiver adopts the optical interface including a tapered cavity and cylindrical cavity, so that a precise mechanical connection can be achieved between the output of laser of the cartridge receiver and the output of the optical fiber of the housing without professional tools, facilitating standardization of the output components of the laser elements of the cartridge receiver. In addition, the upper-lower guide rails and the upper-lower channels having certain of inclination degree can realize the precise positioning of the cartridge receiver and the housing. When replacing one laser element by a laser element that emits laser with a different wavelength, it is only necessary to replace the cartridge receiver inside the housing. That is, the replacement of laser elements having different wavelengths is converted to the replacement of cartridge receivers, which greatly reduces the difficulty for medical personnel to switch laser wavelengths, and improves the popularization of laser therapeutic instruments in the medical field. In the exchangeable laser array of the disclosure, the cartridge receiver inside the housing can be replaced by other cartridge receiver that emits laser with a different wavelength, and the plurality of housings can be connected with a plurality of wavelength switchers in the back to realize selective output of the wavelength.

A CO.sub.2 laser that generates laser-radiation in just one emission band of a CO.sub.2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO.sub.2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

A purging system for a laser system is described. The purging system comprising a cartridge that houses a desiccant material and which is configured for removable mounting with an enclosure of the laser system. The cartridge comprising a first mesh layer that provides a means for a fluid to flow to the desiccant material housed within the cartridge. The purging system further comprises a membrane located over the first mesh layer. The purging system therefore provides a mean for passively purging the laser system and so its operation does not require the employment of a pump. The employment of the removable cartridge also has the advantage that the downtimes of the laser system with which it is deployed are reduced during periods when it is required to dry or replace the desiccant material.

A purging system for a laser system is described. The purging system comprising a cartridge that houses a desiccant material and which is configured for removable mounting with an enclosure of the laser system. The cartridge comprising a first mesh layer that provides a means for a fluid to flow to the desiccant material housed within the cartridge. The purging system further comprises a membrane located over the first mesh layer. The purging system therefore provides a mean for passively purging the laser system and so its operation does not require the employment of a pump. The employment of the removable cartridge also has the advantage that the downtimes of the laser system with which it is deployed are reduced during periods when it is required to dry or replace the desiccant material.

A coherent light source provides spontaneous emission (Dicke superradiance/subradiance) using a dilute and optically thin cloud of disordered atoms. The coherent light source provides improved noise statistics over that of a laser and, accordingly, may be used in sensitive interferometric applications such as light gyroscopes.

Gaseous laser systems and related techniques are disclosed. Techniques disclosed herein may be utilized, in accordance with some embodiments, in providing a gaseous laser system with a configuration that provides (A) pump illumination with distinct edge surfaces for an extended depth and (B) an output beam illumination from a resonator cavity with distinct edges in its reflectivity profile, thereby providing (C) pump beam and output beam illumination on a volume so that the distinct edge surfaces of its pump and beam illumination are shared-edge surfaces with (D) further edge surfaces of the amplifier volume at the surfaces illuminated directly by the pump or output beams, as defined by optical windows and (optionally) by one or more flowing gas curtains depleted of the alkali vapor flowing along those optical windows. Techniques disclosed herein may be implemented, for example, in a diode-pumped alkali laser (DPAL) system, in accordance with some embodiments.