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.

An energy measuring apparatus according to one aspect of the present disclosure includes a first beam splitter, a second beam splitter, a third beam splitter, and a fourth beam splitter, which sequentially reflect part of a main beam and input the beam to an energy sensor. The first beam splitter, the second beam splitter, the third beam splitter, and the fourth beam splitter are each arranged to have such an incident angle and a folding direction of an optical path as to suppress a change in detection value of the energy sensor due to a change in incident angle and a change in polarization purity of the main beam.

A laser apparatus according to the present disclosure includes: a laser chamber including a pair of electrodes and configured to emit, at each of a plurality of pulse repetition frequencies, a pulse laser beam having a pulse energy corresponding to a voltage applied between the electrodes; an energy detector provided on an optical path of the pulse laser beam and configured to detect the pulse energy of the pulse laser beam; a voltage control unit configured to control the applied voltage based on a target pulse energy and the pulse energy detected by the energy detector; and a pulse energy control unit configured to periodically vary the target pulse energy at a modulation frequency corresponding to each of the pulse repetition frequencies with a reference energy being a center of variation.

A laser device, including multiple laser modules, includes a plurality of drive power units that drive the laser modules, a plurality of output detection units that detect laser outputs from the laser modules, and output detected values as first output signals, a coupled output detection unit that detects a total laser output after coupling of a plurality of the laser outputs, and outputs a detected value as a second output signal, a computing unit that sets multiple output correction factors for correspondingly controlling the laser modules using the plurality of first output signals and the second output signal, and a control unit that controls the plurality of drive power units using the multiple output correction factors. The multiple output correction factors are each set to allow the total laser output to be maintained at a constant value.

A laser device, including multiple laser modules, includes a plurality of drive power units that drive the laser modules, a plurality of output detection units that detect laser outputs from the laser modules, and output detected values as first output signals, a coupled output detection unit that detects a total laser output after coupling of a plurality of the laser outputs, and outputs a detected value as a second output signal, a computing unit that sets multiple output correction factors for correspondingly controlling the laser modules using the plurality of first output signals and the second output signal, and a control unit that controls the plurality of drive power units using the multiple output correction factors. The multiple output correction factors are each set to allow the total laser output to be maintained at a constant value.

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.

The present disclosure provides a dark cavity laser, including: a frequency stabilized laser output device configured to generate a laser light, and perform a frequency stabilized processing on the generated laser light to output it to the dark cavity laser device as a pump light of a gain medium of a dark cavity; and a dark cavity laser device including a main cavity, and a cavity of the main cavity is provided inside with a gas chamber of a gain medium of a dark cavity laser light, where the gain medium of the dark cavity laser light is alkali metal atoms; the dark cavity laser device is configured to receive the pump light, and form a polyatomic coherent stimulated radiation between transition levels of the alkali metal atoms in the gas chamber by a weak feedback of the main cavity to generate the dark cavity laser light.

Methods and apparatus for controlling laser firing timing and hence bandwidth in a laser capable of operating at any one of multiple repetition rates.

Methods and apparatus for controlling laser firing timing and hence bandwidth in a laser capable of operating at any one of multiple repetition rates.

An optical pulse stretcher includes a separation optical element configured to separate pulsed laser light incident on a first surface thereof into first transmitted light and first reflected light, a reflective optical system configured to guide the first reflected light to be incident on a second surface of the separation optical element that is the surface opposite the first surface, and a holding member that has a through hole having an opening area smaller than the area of a reflective surface of a reflective optical element provided in the reflective optical system, is disposed on the rear side of the reflective optical element, and is configured to hold the reflective optical element.