A nonlinear crystal including stacked strontium tetraborate SrB.sub.4O.sub.7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency doubling stage of a laser assembly to generate laser output light having a wavelength in the range of about 180 nm to 200 nm. One or more fundamental laser beams are frequency doubled, down-converted and/or summed using one or more frequency conversion stages to generate an intermediate frequency light with a corresponding wavelength in the range of about 360 nm to 400 nm, and then the final frequency converting stage utilizes the nonlinear crystal to double the frequency of the intermediate frequency light to generate the desired laser output light at high power. Methods, inspection systems, lithography systems and cutting systems incorporating the laser assembly are also described.

A laser device includes a laser medium for amplifying seed light, a first optical system for outputting excitation light for exciting the laser medium and causing the excitation light to be incident on the laser medium and input to an excitation region of the laser medium, and a second optical system for causing the seed light of first polarization to be incident on the laser medium at an incidence angle larger than 0 with respect to the laser medium and input to the excitation region.

The present invention relates to a device for amplifying a multi-wavelength laser beam, comprising: a. a first active laser medium having a front face and a rear face which is reflective, inclined with respect to each other at a first non-zero inclination, and b. a second active laser medium having a front face suitable for receiving the beam reflected by the rear face and refracted by the front face of the first active laser medium, and a reflective rear face, inclined with respect to each other at a second non-zero inclination, the first inclination, the second inclination and the orientation of the second active laser medium being such that the sub-beams of each wavelength, forming the output beam of the second active laser medium, are parallel to each other at the output of the second active laser medium.

A solid state laser device includes a seed laser that outputs continuous wave laser seed light, a light intensity changeable unit that changes a light intensity thereof and outputs seed pulse light, a CW excitation laser that outputs continuous wave excitation light, an amplifier that amplifies the seed pulse light and outputs amplified light based on an amplification gain increased by the excitation light, a wavelength conversion unit that converts a wavelength of the amplified light and outputs harmonic light, and a light intensity control unit that allows the light intensity changeable unit to output the seed pulse light after a certain time elapsed from an input of an external trigger signal each time the signal is input and output suppression light that suppresses an increase of the amplification gain in a period after an output of the seed pulse light until an input of a next external trigger signal.

A laser output device includes: a laser oscillator for oscillating a source laser pulse; a pulse extender for temporally extending the source laser pulse oscillated by the laser oscillator; an amplifier for amplifying the laser pulse temporally extended by the pulse extender; the laser pulse filter for filtering a pre-pulse and a post-pulse contained in the amplified laser pulse; and a pulse compressor for temporally compressing the laser pulse which has passed through the laser pulse filter.

A laser apparatus includes: (A) a solid-state laser apparatus that outputs burst seed pulsed light containing a plurality of pulses; (B) an excimer amplifier that amplifies the burst seed pulsed light in a discharge space in a single occurrence of discharge and outputs the amplified light as amplified burst pulsed light; (C) an energy sensor that measures the energy of the amplified burst pulsed light; and (D) a laser controller that corrects the timing at which the solid-state laser apparatus is caused to output the burst seed pulsed light based on the relationship of the difference between the timing at which the solid-state laser apparatus outputs the burst seed pulsed light and the timing at which the discharge occurs in the discharge space with a measured value of the energy.

A solid state laser device includes a seed laser that outputs continuous wave laser seed light, a light intensity changeable unit that changes a light intensity thereof and outputs seed pulse light, a CW excitation laser that outputs continuous wave excitation light, an amplifier that amplifies the seed pulse light and outputs amplified light based on an amplification gain increased by the excitation light, a wavelength conversion unit that converts a wavelength of the amplified light and outputs harmonic light, and a light intensity control unit that allows the light intensity changeable unit to output the seed pulse light after a certain time elapsed from an input of an external trigger signal each time the signal is input and output suppression light that suppresses an increase of the amplification gain in a period after an output of the seed pulse light until an input of a next external trigger signal.

Disclosed are optical arrangements including: a disk-shaped laser-active medium, a deflecting device, having a plurality of mirror elements on which mirror faces for deflecting a laser beam are formed, and having a base body on which the mirror elements are fastened, the mirror faces of the mirror elements being oriented in such a way that the laser beam is deflected by a respective mirror face via the disk-shaped laser-active medium to another mirror face. The mirror elements are formed in one piece or are monolithically joined, and have a connecting section that is formed rotationally symmetrically with respect to a center axis and is rigidly connected by a material-fit connection or a direct connection to the base body.

A multi-stage optical amplifier has an input port for receiving an optical signal and a relatively short erbium doped optical fiber is coupled to the input port. Complex costly pump feedback is not required as a constant non-varying saturation pump is configured to provide non varying output power pump light of a predetermined wavelength suitable for excitation and full saturation of the erbium ions such that a full population inversion occurs. The length of the short erbium doped fiber and rare earth doping concentration of the erbium doped fiber is such that when pumped by said pump provides amplification of the optical signal of less than 15 dB. Locating a gain flattening filter after the short erbium doped optical fiber provides a relatively flat amplified output signal. Multi-stages of similar short erbium doped fibers pumped and saturated by the same pump signal economically provide increased amplification of the signal and filters after each state flatten the gain.

A multi-stage optical amplifier has an input port for receiving an optical signal and a relatively short erbium doped optical fiber is coupled to the input port. Complex costly pump feedback is not required as a constant non-varying saturation pump is configured to provide non varying output power pump light of a predetermined wavelength suitable for excitation and full saturation of the erbium ions such that a full population inversion occurs. The length of the short erbium doped fiber and rare earth doping concentration of the erbium doped fiber is such that when pumped by said pump provides amplification of the optical signal of less than 15 dB. Locating a gain flattening filter after the short erbium doped optical fiber provides a relatively flat amplified output signal. Multi-stages of similar short erbium doped fibers pumped and saturated by the same pump signal economically provide increased amplification of the signal and filters after each state flatten the gain.