Abstract: The machining device is equipped with a fiber laser oscillator for oscillating laser light of a top hat shape, and a light collecting lens and a machining head for collecting the laser light of the top hat shape and emitting the laser light onto a machining target such that the beam diameter of the laser light of the top hat shape at a position where light intensity becomes the one corresponding to a machining threshold of the machining target is about three times the size of the beam diameter of laser light in a Gaussian mode at the same position, when the laser light in the Gaussian mode has a beam quality substantially the same as that of the laser light of the top hat shape.

Abstract: In a laser apparatus, when no voltage is applied to optical modulator, a first linearly polarized component of a laser beam which passes through a polarization control mirror causes a laser oscillation in a first laser resonator and a laser beam is output from a second reflecting mirror. When a pulsed voltage is applied to the optical modulator, a second linearly polarized component of the laser beam reflected by the polarization control mirror passes through the optical modulation means and causes a Q-switched laser oscillation in a second laser resonator. In this case, the first linearly polarized component passes through the polarization control mirror and is output from the second reflecting mirror. This technique makes it possible to combine a Q-switched laser apparatus with a non-Q-switched laser apparatus without causing the power of the laser beam to exceed a maximum allowable limit that an electrooptical modulator can handle.

Abstract: A laser system wherein, in order that a high-output and high-quality single mode of a cross sectional area larger than the beam diameter determined by the construction of a resonator can be obtained stably, although this has heretofore been impossible, there is used a coupling mirror provided with a partial reflection film and an antireflecting film, a laser beam mode is selected using the partial reflection film, a phase difference between laser beam portions caused by a difference in construction between the partial reflection film and the antireflecting film is compensated using a phase difference compensating means, and there is formed an aperture whose diameter is set to a value of not larger than four times the diameter of the partial reflection film.

Abstract: A laser system wherein, in order that a high-output and high-quality single mode of a cross sectional area larger than the beam diameter determined by the construction of a resonator can be obtained stably, although this has heretofore been impossible, there is used a coupling mirror provided with a partial reflection film and an antireflecting film, a laser beam mode is selected using the partial reflection film, a phase difference between laser beam portions caused by a difference in construction between the partial reflection film and the antireflecting film is compensated using a phase difference compensating apparatus, and there is formed an aperture whose diameter is set to a value of not larger than four times the diameter of the partial reflection film.

Abstract: According to the present invention there is provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein discharge is obliquely generated within the rectangular section of a discharge space. There is also provided a laser apparatus with a pair of preliminary discharge excitation electrodes which can readily initiate discharge. There is further provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein provided is a pair of discharge excitation electrodes located in the major side direction of discharge space whose length is more than three times as long as that of minor side direction thereof. There is further provided a laser apparatus with a pair of discharge excitation electrodes whose dimension is smaller than that of a pair of dielectric plates, which apparatus can prevent undesirable discharge.

Abstract: According to the present invention there is provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein discharge is obliquely generated within the rectangular section of a discharge space. There is also provided a laser apparatus with a pair of preliminary discharge excitation electrodes which can readily initiate discharge. There is further provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein provided is a pair of discharge excitation electrodes located in the major side direction of discharge space whose length is more than three times as long as that of minor side direction thereof. There is further provided a laser apparatus with a pair of discharge excitation electrodes whose dimension is smaller than that of a pair of dielectric plates, which apparatus can prevent undesirable discharge.