A laser processing method includes providing a unit configured to obtain time t0 from a time when the high-frequency pulse RF output is turned on to a time when the laser is actually output in advance and change a traveling direction of the laser in an optical path of the laser, irradiating the workpiece with all the lasers while the high-frequency pulse RF output is turned on, and removing at least a part of the laser from the workpiece simultaneous with turning off the high-frequency pulse RF output.

A system and method for making vias in a laminated printed circuit board (PCB). A drill having both a mechanical drill and a laser drill is used to make the via. The mechanical drill is moved over a location in the PCB where a blind via is desired. The mechanical drill drills to a point where a tip of a bit of the mechanical drill is a predetermined distance above a target interconnect layer. Then the drill is moved such that the laser drill is located over the via where the mechanical drill had drilled the via. The laser drill then ablates the resin remaining above the target interconnect layer.

An extreme ultraviolet light generation system may include a chamber, a first partition wall having at least one opening which provides communication between a first space and a second space, an EUV light concentrating mirror located in the second space and configured to concentrate extreme ultraviolet light generated in a plasma generation region located in the first space, a first gas supply port formed at the chamber, and a gas exhaust port formed in the first partition wall, a distance between the center of the plasma generation region and an edge of the at least one opening being equal to or more than a stop distance L.sub.STOP [mm] calculated by the following equation:
L.sub.STOP=272.8.Math.E.sub.AVG.sup.0.4522.Math.P.sup.−1 E.sub.AVG [eV] representing average kinetic energy of ions generated in the plasma generation region and P [Pa] representing a gas pressure inside the first partition wall.

An improved dental laser system has been developed to cut enamel quickly and precisely, without detrimental residual energy, to provide a replacement for conventional high speed rotary burrs and commercially available dental laser systems.

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.

A laser assembly for additive manufacturing which includes a first laser beam aligned in a first direction and a first partial reflecting fixed mirror positioned aligned with the first direction which reflects a first portion of the first laser beam in a second direction and an exponentially reduced remaining second portion of the first laser beam passes through the first partial reflecting fixed mirror in the first direction. The laser beam assembly further includes a first oscillating mirror positioned aligned with the second direction of the first portion of the first laser beam wherein the first portion of the first laser beam is refracted by the first oscillating mirror in a third direction.

A control device that can apply a laser oscillator control device to various types of systems. The control device includes an analog signal input unit configured to receive an output control signal for controlling a laser output of the laser oscillator or a mode control signal for controlling an operation mode of the laser oscillator as an analog signal; a digital signal input unit configured to receive the output control signal or the mode control signal as a digital signal; and a controller configured to transmit a laser command for controlling the laser output to the laser oscillator in response to the output control signal received by the analog signal input unit or the digital signal input unit, and transmit an operation command for operating the laser oscillator to the laser oscillator in the operation mode in response to the mode control signal received by the analog signal input unit or the digital signal input unit.

A light source capable of operating third and fourth reflection mirrors included in a beam splitting device in conjunction with movements of first and second reflection mirrors included in a beam transfer device and an optical assembly, respectively. The third and fourth reflection mirrors are disposed on optical paths of a pre-pulse and a main pulse emitted from first and second pulse generators, respectively. The light source operates the third and fourth reflection mirrors to offset an excessive compensation of the main pulse caused in a process of compensating for an optical path error of the pre-pulse. The light source may be included in an extreme ultraviolet light source system.

A method of manufacturing a semiconductor includes generating plasma in an amplifying tube using gas as a gain medium; detecting a state of the plasma generated in the amplifying tube; determining a virtual laser gain based on the detected state of the plasma; controlling the state of the plasma such that the virtual laser gain is within a target range; and manufacturing the semiconductor device including performing an exposure process on a substrate using a laser beam output from the amplifying tube adjusted to have the virtual laser gain within the target range.

A device includes a laser source, an amplifier, an optical sensor and a spectrometer. The laser source is configured to produce a seed laser beam. The amplifier includes gain medium and a discharging unit. The discharging unit is configured to pump the gain medium for amplifying power of the seed laser beam. The optical sensor is coupled to the amplifier and configured for sensing an optical emission generated in the amplifier while the gain medium is discharging. The spectrometer is coupled with the optical sensor and configured to measure a spectrum of the optical emission.