A laser apparatus according to an aspect of the present disclosure includes a laser oscillator configured to emit a pulse laser beam, and a first optical pulse stretcher, a second optical pulse stretcher, and a third optical pulse stretcher that are disposed on an optical path of the pulse laser beam. When L1 represents an optical path length of a delay optical path of the first optical pulse stretcher, L2 represents an optical path length of a delay optical path of the second optical pulse stretcher, L3 represents an optical path length of a delay optical path of the third optical pulse stretcher, and n represents an integer equal to or larger than two, L2 is an integral multiple of L1 by an integer equal to or larger than two and L3 satisfies the following condition: (n−0.75)×L1≤L3≤(n−0.25)×L1.

A laser apparatus according to an aspect of the present disclosure includes a laser oscillator configured to emit a pulse laser beam, and a first optical pulse stretcher, a second optical pulse stretcher, and a third optical pulse stretcher that are disposed on an optical path of the pulse laser beam. When L1 represents an optical path length of a delay optical path of the first optical pulse stretcher, L2 represents an optical path length of a delay optical path of the second optical pulse stretcher, L3 represents an optical path length of a delay optical path of the third optical pulse stretcher, and n represents an integer equal to or larger than two, L2 is an integral multiple of L1 by an integer equal to or larger than two and L3 satisfies the following condition: (n−0.75)×L1≤L3≤(n−0.25)×L1.

Apparatus for and method of aligning optical components such as mirrors to facilitate proper beam alignment using an image integration optical system is used to integrate images from multiple optical features such as from both left mirror bank and right mirror bank to present the images simultaneously to the camera system. A fluorescent material may be used to render a beam footprint visible and the relative positions of the footprint and an alignment feature may be used to align the optical feature.

A laser apparatus includes an oscillator, a rotary stage that supports an optical element, a grating, a first driving mechanism that changes the angle of incidence of pulse laser light to be incident on the grating by driving the rotary stage, a second driving mechanism that changes the angle of incidence of the pulse laser light to be incident on the grating by driving the rotary stage by a smaller amount, a wavelength monitor, and a processor that cyclically changes a target wavelength of the pulse laser light. The processor calculates the moving average of drive instruction values by which the second driving mechanism is driven, and when the moving average exceeds a threshold, the processor causes the second driving mechanism to return to an initial position, and drives the first driving mechanism to cancel a change in the angle of incidence caused by the returning operation.

A spectral feature selection apparatus includes a dispersive optical element arranged to interact with a pulsed light beam; three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and a pulsed optical source; and one or more actuation systems, each actuation system associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam. At least one of the actuation systems is a rapid actuation system that includes a rapid actuator configured to rotate its associated refractive optical element about a rotation axis. The rapid actuator includes a rotary stepper motor having a rotation shaft that rotates about a shaft axis that is parallel with the rotation axis of the associated refractive optical element.

A laser light source is provided including an airtight container. A first resonance mirror and a second resonance mirror are disposed outside the airtight container. The first resonance mirror includes a lens unit and a reflection coating layer. The lens unit includes a first surface and a second surface, and the first surface is inclined with respect to the second surface.

An apparatus includes a decision module that is configured to: receive a performance metric relating to performance conditions of an optical system emitting a light beam; estimate, based on the performance metric and a predetermined learning model, an effectiveness of a proposed change to the optical system; and output a change command to the optical system if it is estimated that the proposed change to the optical system would be effective.

Provided is a light source apparatus and an electrode design for use in a discharge chamber of the light source apparatus. The discharge chamber is configured to hold a gas discharge medium configured to output a light beam. The light source apparatus include a pair of opposed electrodes configured to excite a gas medium to form a discharge plasma. At least one electrode of the pair of opposing electrodes may include recessed portions or hollowed-out portions at each end of the electrode, or at other suitable locations. The disclosed electrode structures improve uniformity of the erosion profile of the electrodes, significantly extending the lifespan of the discharge chamber by redistributing the discharge particle flux through the electrode with an optimized design of the electrode geometry, as the local discharge particle flux is reduced at the recessed portions.

Provided is a light source apparatus and an electrode design for use in a discharge chamber of the light source apparatus. The discharge chamber is configured to hold a gas discharge medium configured to output a light beam. The light source apparatus include a pair of opposed electrodes configured to excite a gas medium to form a discharge plasma. At least one electrode of the pair of opposing electrodes may include recessed portions or hollowed-out portions at each end of the electrode, or at other suitable locations. The disclosed electrode structures improve uniformity of the erosion profile of the electrodes, significantly extending the lifespan of the discharge chamber by redistributing the discharge particle flux through the electrode with an optimized design of the electrode geometry, as the local discharge particle flux is reduced at the recessed portions.

The present disclosure is directed to systems and methods for controlling a center wavelength. In one example, a method includes estimating a center wavelength error. The method also includes determining a first actuation amount for a first actuator controlling movement a first prism based on the estimated center wavelength error. The method also includes actuating the first actuator based on the actuation amount. The method also includes determining whether the first prism is off-center. The method also includes, in response to determining that the first prism is off-center, determining a second actuation amount for the first actuator and determining a third actuation amount for a second actuator for controlling movement of a second prism. The method also includes actuating the first actuator and the second actuator based on the second and third actuation amounts, respectively. The method finds application in multi-focal imaging operations.