Some embodiments may include a fiber laser system comprising: a pump combiner; a plurality of fiber laser pump modules arranged for pumping a pulsed output from the fiber laser system; and a pump controller to operate in a first operation mode to pump a pulsed output from the fiber laser system and to operate in a second different operation mode to pump a continuous wave (CW) output from the fiber laser system; the pump controller to, in the first operation mode, simultaneously activate individual fiber laser pump modules of the plurality of fiber laser pump modules; and the pump controller to, in the second operation mode, sequentially activate the individual fiber laser pump modules of the plurality of fiber laser pump modules. Other embodiments may be disclosed and/or claimed.

Some embodiments may include a fiber laser system comprising: a pump combiner; a plurality of fiber laser pump modules arranged for pumping a pulsed output from the fiber laser system; and a pump controller to operate in a first operation mode to pump a pulsed output from the fiber laser system and to operate in a second different operation mode to pump a continuous wave (CW) output from the fiber laser system; the pump controller to, in the first operation mode, simultaneously activate individual fiber laser pump modules of the plurality of fiber laser pump modules; and the pump controller to, in the second operation mode, sequentially activate the individual fiber laser pump modules of the plurality of fiber laser pump modules. Other embodiments may be disclosed and/or claimed.

A solid-state laser system includes a gain medium having an optical resonator defined therein. The gain medium is co-doped with first and second active elements. The first active element is Er.sup.3+ and the second active element is Ho.sup.3+ or Dy.sup.3+. The solid-state laser system also includes a pump source coupled to the gain medium for pumping the gain medium with pump light.

A laser apparatus according to the present disclosure includes an excitation light source configured to output excitation light, a laser crystal disposed on an optical path of the excitation light, a first monitor device disposed on an optical path of transmitted excitation light after having transmitted through the laser crystal to monitor the transmitted excitation light, a temperature adjustment device configured to adjust a temperature of the excitation light source to a constant temperature based on a temperature command value, and a controller configured to change the temperature command value based on a result of monitoring by the first monitor device.

A laser apparatus according to the present disclosure includes an excitation light source configured to output excitation light, a laser crystal disposed on an optical path of the excitation light, a first monitor device disposed on an optical path of transmitted excitation light after having transmitted through the laser crystal to monitor the transmitted excitation light, a temperature adjustment device configured to adjust a temperature of the excitation light source to a constant temperature based on a temperature command value, and a controller configured to change the temperature command value based on a result of monitoring by the first monitor device.

Disclosed is a laser system including a first laser and a second laser. The first laser includes a laser cavity, and a gas phase molecular gain medium disposed in the laser cavity, the gain medium having an absorption band. The second laser is a solid state laser configured to be continuously tunable, with respect to an emission wavelength of the second laser, over the absorption band of the gain medium, and the second laser is tuned to pump rotational vibrational transitions in the gain medium to achieve a rotational population inversion.

An ultraviolet laser apparatus includes: a semiconductor laser that emits an excitation laser light; a fiber laser medium to which the excitation laser light enters from the semiconductor laser and that causes laser oscillation; and an external resonator that: converts a wavelength of a laser light oscillated in the fiber laser medium, and outputs an ultraviolet region continuous wave of at least 0.1W.

An ultraviolet laser apparatus includes: a semiconductor laser that emits an excitation laser light; a fiber laser medium to which the excitation laser light enters from the semiconductor laser and that causes laser oscillation; and an external resonator that: converts a wavelength of a laser light oscillated in the fiber laser medium, and outputs an ultraviolet region continuous wave of at least 0.1W.

A laser device according to one embodiment includes a laser light source configured to output pulsed laser light L1 and a pulse width control unit configured to amplify the pulsed laser light output from the laser light source, change a pulse width of the pulsed laser light, and output the pulsed laser light. The pulse width control unit includes a first laser amplifier configured to amplify the pulsed laser light and a pulse waveform manipulation unit disposed between the first laser amplifier and the laser light source and configured to manipulate a pulse waveform of the pulsed laser light.

An exposure system according to an aspect of the present disclosure includes a laser apparatus emitting a pulse laser beam, an illumination optical system guiding the pulse laser beam to a reticle, a reticle stage moving the reticle, and a processor controlling emission of the pulse laser beam and movement of the reticle. The exposure system performs scanning exposure of a semiconductor substrate by irradiating the reticle with the pulse laser beam. The reticle has first and second regions. The processor instructs the laser apparatus about, based on proximity effect characteristics corresponding to the first and second regions, a value of a control parameter of the pulse laser beam corresponding to each region so that the laser apparatus emits the pulse laser beam with which a difference of the proximity effect characteristic of each region from a reference proximity effect characteristic is in an allowable range.