Abstract: A gas laser device includes a chamber device including electrodes at an inside thereof to be filled with laser gas and configured to output, through a window to an outside thereof, light generated from the laser gas when a voltage is applied to the electrodes; a mirror arranged at the outside of the chamber device and configured to reflect at least a part of the light output through the window; a holding portion holding the mirror; a support member configured to support the holding portion to be movable along a plane perpendicular to an optical axis of the light output through the window; a moving mechanism configured to move the holding portion with respect to the support member along the plane; and an angle maintaining mechanism configured to maintain an inclination angle of the holding portion with respect to the support member at a predetermined angle.

Abstract: An image forming apparatus includes image bearers, motors, a reference position detector, and processing circuitry. The circuitry senses a density of a toner image on each bearer; forms an image pattern and senses, based on a detection result of the detector and a sensing result of the density, density unevenness in a rotation cycle and a phase of the density unevenness with respect to a rotational position reference of each bearer; calculates a target phase based on the phase sensed; calculates a relative phase difference based on a rotational position and the target phase of each bearer; selects, as a reference image bearer, an image bearer having a minimum phase correction value, based on a calculation result of the difference; and controls the rotational position of each of the other image bearers with respect to the reference image bearer to the phase correction value, with the motors being driven.

Abstract: 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.

Abstract: A laser system may include a plurality of laser apparatuses, a beam delivery device configured to bundle pulse laser beams emitted from respective laser apparatuses of the plurality of laser apparatuses to emit a bundled laser beam, and a controller configured to control operated laser apparatuses of the plurality of laser apparatuses such that, at a change in a number representing how many laser apparatuses are operated, a beam parameter of the bundled laser beam emitted from the beam delivery device approaches a beam parameter of the bundled laser beam emitted before the change.

Abstract: A narrow band laser apparatus may include: a laser chamber; a line narrow module configured to narrow a band width of a laser beam outputted from the laser chamber and return the laser beam to the laser chamber, the line narrow module including a grating; a housing accommodating the line narrow module; three mounts fixed to the housing; and a housing moving device configured to support the housing and the line narrow module by supporting each of the three mounts and move the line narrow module by moving the housing with respect to the laser chamber in a direction substantially perpendicular to a dispersion plane of the grating.

Abstract: A laser system may include a plurality of laser apparatuses, a beam delivery device configured to bundle pulse laser beams emitted from respective laser apparatuses of the plurality of laser apparatuses to emit a bundled laser beam, and a controller configured to control operated laser apparatuses of the plurality of laser apparatuses such that, at a change in a number representing how many laser apparatuses are operated, a beam parameter of the bundled laser beam emitted from the beam delivery device approaches a beam parameter of the bundled laser beam emitted before the change.