A beam reverser module for an optical power amplifier of a laser arrangement comprises at least one reflecting surface for receiving an incoming laser beam propagating in a first direction and reflecting the incoming laser beam into a second direction different from the first direction, wherein the at least one reflecting surface is a highly reflecting surface of at least one mirror.

A narrowband laser apparatus may be provided with a laser resonator including optical elements for narrowing a spectral linewidth, a spectrometer configured to detect spectral intensity distributions of multiple pulses included in a pulsed laser beam output from the laser resonator, a spectral waveform producer configured to produce a spectral waveform by adding up the spectral intensity distributions of the multiple pulses, a device function storage configured to store a device function of the spectrometer, a wavelength frequency function generator configured to generate a wavelength frequency function which represents a frequency distribution of center wavelengths of the multiple pulses, and a deconvolution processor configured to perform deconvolution processing on the spectral waveform with the device function and the wavelength frequency function.

Online calibration of laser performance as a function of the repetition rate at which the laser is operated is disclosed. The calibration can be periodic and carried out during a scheduled during a non-exposure period. Various criteria can be used to automatically select the repetition rates that result in reliable in-spec performance. The reliable values of repetition rates are then made available to the scanner as allowed values and the laser/scanner system is then permitted to use those allowed repetition rates.

A laser apparatus according to the present disclosure includes: a laser output unit configured to perform laser oscillation; and a control unit configured to acquire first laser performance data obtained when the laser output unit performs laser oscillation based on a first laser control parameter, and second laser performance data obtained when the laser output unit performs laser oscillation based on a second laser control parameter, while laser output from the laser output unit to an external device is stopped, and determine whether the second laser performance data has been improved as compared to the first laser performance data.

Methods and systems for sterilizing a tools and equipment are disclosed, including using a UV source to generate a pulsed UV light within or exterior to an enclosure having a highly reflecting diffuse inner coated surface; and absorbing the pulsed light to sterilize. Other embodiments are described and claimed.

A set of optical elements for optical extraction composed of packed expanding optical cross sections to efficiently extract from a large gain region. The elements are rectangular shaped concave small expansion lenses matched to rectangular convex collimating lenses. Absorbing sheets divide an overall large volume up into smaller volumes to minimize losses due to amplified spontaneous emission. This arrangement has various applications, particularly in inertial confinement technology, where it may be used to extract energy from KrF laser media energized by electron beams. For certain applications, this regime of the gain medium may have zones at the absorbing sheets where this is no gain.

A line narrowing module includes a prism that refracts laser light in a first plane, a grating that disperses the laser light in the first plane, first to fourth elements, and a rotation mechanism and narrows the linewidth of the laser light. The second element is supported between the first and fourth elements by the first element. The rotation mechanism rotates the second element relative to the first element around an axis intersecting the first plane. The prism is located between the second and fourth elements and so supported by the second element that the rotation mechanism rotates the prism and the second element. The third element has elasticity and is compressed and located between the prism and the fourth element. The fourth element receives reaction force from the compressed third element. The second element is mechanically independent of the fourth element in the rotational direction of the rotation mechanism.

A rectangular electrical pulse enters a transmission line structure with single pass transit time equal to the duration of the pulse, open circuit at the extreme end and a switch at its center. After a delay equal to of the rectangular pulse duration the central switch is closed to couple the contents of the transmission line structure into another transmission line of half impedance. The output pulse maintains the initial voltage, but is of half the initial duration, and double the initial power.

A line-narrowed KrF excimer laser apparatus includes a laser chamber, a line narrow optical system, an actuator, an output coupling mirror, a wavelength detecting unit, and a wavelength controller. The actuator is capable of changing a wavelength of light selected by the line narrow optical system. The wavelength detecting unit includes a low-pressure mercury lamp accommodating mercury, a getter material that adsorbs at least a part of the mercury, and a hot cathode that excites at least a part of the mercury, an etalon provided at a position where reference light emitted from the low-pressure mercury lamp and detected light emitted from the output coupling mirror are incident on the etalon, and a light intensity distribution sensor configured to detect an intensity distribution profile of interference fringes of the reference light and an intensity distribution profile of interference fringes of the detected light.

A laser apparatus includes first and second wavelength dispersion elements, an optical element, first and second actuators, and a control unit. The first wavelength dispersion element generates wavelength dispersion in a direction orthogonal to an electric discharge direction between a pair of electric discharge electrodes. The second wavelength dispersion element generates wavelength dispersion in a direction parallel to the electric discharge direction. The optical element corrects wavelength dispersion generated by the second wavelength dispersion element. The first actuator drives the first wavelength dispersion element. The second actuator drives the optical element. The control unit controls the first actuator so that the center wavelength of the laser light approaches to a target wavelength and controls the second actuator so as to correct the wavelength dispersion generated by the second wavelength dispersion element.