Methods, systems, and devices are described. A system may include an optically transmissive substrate having a protective coating on a first surface and a blocking coating on a second surface that is opposite the first surface. The protective coating is configured to protect the optically transmissive substrate from at least ultraviolet laser energy, and the blocking coating has a first thickness that is less than about 280 nanometers and is adhered to a subset of the second surface. The system further includes a capping layer covering the blocking coating that is on the subset of the second surface and having a second thickness less than the first thickness of the blocking coating. Additionally, the system includes a sealing component positioned between the capping layer and a structure configured to support the optically transmissive substrate.

A gas laser, including: a semiconductor laser, an optical beam-shaping system, a pair of electrodes, a discharge tube, a rear mirror, and an output mirror. The pair of electrodes includes two electrodes. The electrodes are symmetrically disposed at an outer layer of the discharge tube in parallel. The electrodes are connected to a radio-frequency power supply via a matching network, and the electrodes operate to modify working gas in the discharge tube through radio-frequency discharge. The rear mirror and the output mirror are disposed at two end surfaces of the discharge tube, respectively. The rear mirror, taken together with the output mirror and the discharge tube, form a resonant cavity. The output mirror is configured to output a laser beam.

A gas laser, including: a semiconductor laser, an optical beam-shaping system, a pair of electrodes, a discharge tube, a rear mirror, and an output mirror. The pair of electrodes includes two electrodes. The electrodes are symmetrically disposed at an outer layer of the discharge tube in parallel. The electrodes are connected to a radio-frequency power supply via a matching network, and the electrodes operate to modify working gas in the discharge tube through radio-frequency discharge. The rear mirror and the output mirror are disposed at two end surfaces of the discharge tube, respectively. The rear mirror, taken together with the output mirror and the discharge tube, form a resonant cavity. The output mirror is configured to output a laser beam.

A laser resonator comprising a specially designed front mirror 32. The front mirror 32 together with a rear mirror form a resonator cavity. As well as having a resonator cavity reflective surface 42, the front mirror 32 also has an output coupling reflective surface 44 which forms a continuation of the resonator cavity reflective surface 42 and extends at an angle thereto so as to direct a beam laterally out of the cavity. The output coupling reflective surface 44 and the resonator cavity reflective surface 44 are joined by a “soft” rounded edge 40 of arcuate cross-section, this rounded transition suppressing diffraction ripples that would otherwise be generated if the edge were “hard”, i.e. sharp.

An example of the disclosure is a laser apparatus including a master oscillator capable of outputting a pulse laser beam, a plurality of optical amplifiers disposed on an optical path of the pulse laser beam outputted from the master oscillator and configured to sequentially amplify the pulse laser beam, an optical reflector capable of passing the pulse laser beam therethrough and reflecting a self-oscillation beam generated in one of the plurality of optical amplifiers, and an optical absorber capable of receiving and absorbing the self-oscillation beam reflected by the optical reflector.

The disclosure concerns a housing for a light source mounted on a substrate, the housing comprising: a barrel comprising a mounting for a diffuser; and a diffuser positioned in the mounting, wherein the barrel comprises first and second conducting columns and a fuse or conductive wire electrically coupling the first and second conducting columns. A portion of the fuse is mechanically fixed to the diffuser and/or the fuse being arranged to trap the diffuser in said mounting.

The disclosure concerns a housing for a light source mounted on a substrate, the housing comprising: a barrel comprising a mounting for a diffuser; and a diffuser positioned in the mounting, wherein the barrel comprises first and second conducting columns and a fuse or conductive wire electrically coupling the first and second conducting columns. A portion of the fuse is mechanically fixed to the diffuser and/or the fuse being arranged to trap the diffuser in said mounting.

A light emitting sealed body includes: a housing which stores a discharge gas and is provided with a first opening to which first light is incident along a first optical axis and a second opening from which second light is emitted along a second optical axis; a first window portion which hermetically seals the first opening; a second window portion which hermetically seals the second opening; and a first electrode and a second electrode. The housing is formed of a light shielding material which does not transmit the first light and the second light. An internal space is defined by the housing, the first window portion, and the second window portion and the internal space is filled with the discharge gas. The first opening and the second opening are disposed so that the first optical axis and the second optical axis intersect each other.

A light emitting sealed body includes: a housing which stores a discharge gas and is provided with a first opening to which first light is incident along a first optical axis and a second opening from which second light is emitted along a second optical axis; a first window portion which hermetically seals the first opening; a second window portion which hermetically seals the second opening; and a first electrode and a second electrode. The housing is formed of a light shielding material which does not transmit the first light and the second light. An internal space is defined by the housing, the first window portion, and the second window portion and the internal space is filled with the discharge gas. The first opening and the second opening are disposed so that the first optical axis and the second optical axis intersect each other.

A gas laser device includes a shielding plate that is a first shielding member, and a shielding plate that is a second shielding member. The first shielding member includes a first opening, and a second opening. A laser beam that is to be propagated to discharge regions passes through the first opening. The laser beam that has taken a round trip through the discharge regions after passing through the first opening passes through the second opening. The second shielding plate faces the first shielding member the discharge regions located therebetween. The shielding plate includes an opening that is a third opening. The laser beam that has been propagated through the first opening and the discharge regions, and the laser beam that is to be propagated to the second opening through the discharge regions pass through the third opening. A plane shape of the third opening includes a rectilinear segment.