A system for producing single-frequency or near-single-frequency operation of a laser beam includes a laser for emitting a laser beam at each one of a plurality of cavity lengths, A detector is configured to receive at least a portion of the laser beam emitted, and generate a signal. A computer system is configured to identify at least one beat note in the signal for each of at least one of the plurality of cavity lengths, the at least one beat note indicating the presence of one or more higher-order transverse modes, longitudinal modes, or both, in the received at least the portion of the laser beam emitted at the at least one of the plurality of cavity lengths. The cavity is adjusted to one of the plurality of cavity lengths for eliminating or minimizing the at least one beat note.

An extreme ultraviolet (EUV) light concentrating apparatus including a main body having a concave inner portion and configured to rotate, a tin generator configured to generate tin drops and spray the tin drops, a tin catcher configured to process the sprayed tin drops, a protective cover configured to block the tin drops from falling into the main body, and a rotation guide configured to rotate the main body may be provided.

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 laser device may include a light source configured to emit a laser beam in burst operation, an optical sensor configured to acquire a cross sectional image of the laser beam during a certain period for every certain cycle, an image processor configured to receive an input of an image signal of the cross sectional image outputted from the optical sensor and output beam relating information about the laser beam, a beam traveling direction adjuster configured to adjust a traveling direction of the laser beam, and a controller configured to control the beam traveling direction adjuster based on the beam relating information when at least a part of a period in which the optical sensor acquires the cross sectional image is overlapped with a period in which the light source emits a laser beam.

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).

A laser device includes: a master oscillator (100) configured to output a pulse laser beam (L) based on a light emission trigger signal (S21); a delay circuit (153) configured to generate a switching signal (S10) after a predetermined delay time has elapsed since reception of the light emission trigger signal (S21); a high voltage switch (304) configured to generate a high voltage pulse based on the switching signal (S10); an optical shutter (32k) positioned on the optical path of the pulse laser beam (L) and driven based on the high voltage pulse; and a high voltage monitor (151) configured to detect the high voltage pulse and transmit a high voltage pulse sensing signal (S6) to the delay circuit (153). The delay circuit (153) determines the delay time based on the light emission trigger signal (S21) and the high voltage pulse sensing signal (S6).

A system includes a laser source operable to provide a laser beam, a laser amplifier having a gain medium operable to provide energy to the laser beam when the laser beam passes through the laser amplifier, and a residual gain monitor operable to provide a probe beam and operable to derive a residual gain of the laser amplifier from the probe beam when the probe beam passes through the laser amplifier while being offset from the laser beam in time or in path.

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.

A dual-laser cutting machine includes a cutting machine having a machine body. The bottom of the machine body is provided with a bottom base mounting a working platform for fixing a workpiece. The machine body mounts a compound cutter base, which can move relative to the machine body to adjust the relative position between the compound cutter base and the working platform. The compound cutter base mounts a UV laser generator and a CO.sub.2 laser generator. First, fix the workpiece. Then, use the UV laser generator to emit the low-power UV nano laser to punch the predetermined cutting line of the workpiece to create holes thereon. As the holes are very close to each other, there are many cracks formed therebetween. Afterward, use the CO.sub.2 laser generator to emit the CO.sub.2 laser in defocus status to cut the path formed by the holes.

The concentration of substance in blood is measured non-invasively, with high accuracy and with simple configuration. Laser light 100 generated by a light source 10 is locally irradiated on the body epithelium F of a subject, and the resulting diffused reflected light 200 is detected by a light detector 40. The laser light 100 has a wavelength of 9.26 m. The laser light 100 is generated by converting and amplifying pulsed excitation light 101 from an excitation light source 11 to a long wavelength. A plate-shaped window 300 that is transparent to mid-infrared light is brought in close contact with the body epithelium F. The glucose concentration in interstitial fluid can be calculated using normalized light intensity calculated from a signal ratio of signals from a monitoring light detector 16 and light detector 40.