There are provided: a planar waveguide in which claddings (2) and (3) each having a smaller refractive index than a laser medium for absorbing pump light (5) are bonded to an upper surface (1a) and a lower surface (1b) of a core (1) which is formed from the laser medium; pump light generation sources (4a) and (4b) for emitting pump light (5) to side surfaces (1c) and (1d) of the core (1); and laser light high reflection films (6a) and (6b) formed on side surfaces (1e) and (1f) of the core (1). Each of side surfaces (2e) and (2f) of the cladding (2) corresponding to the side surfaces (1e) and (1f) of the core (1) has a ridge structure (20) in which a part thereof is recessed.

Both of multi-mode laser beam 8A and excitation beam 34A for amplification are imputed to an amplification gain medium 62 in a relationship in which their optical axes match each other and an effective beam diameter of the excitation beam for amplification is smaller than an effective beam diameter of the multi-mode laser beam. As a result, laser beam of a part of modes progressing in a radiation range of the excitation beam 34A for amplification is selectively amplified. Laser beam 40A subjected to mode cleaning is thereby outputted.

Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

A resonator for a laser includes a first resonator wall and a second resonator wall with a lasing medium disposed in a gap therebetween. The resonator further includes a first mirror disposed at a first end of the first and second resonator walls and a second mirror disposed at a second end of the first and second resonator walls. The mirrors cooperate to form an intra-cavity laser beam that travels along a plurality of paths through the lasing medium. Furthermore, the first mirror and the second mirror form a laser resonator for a parasitic laser mode. A parasitic mode suppressor is located within the superfluous region.

A method and a laser for breaking through the limitation of fluorescence spectrum on laser wavelength is disclosed. The method includes: exciting electrons to a high energy level by pump light, and suppressing an oscillation of radiation light by laser cavity coating, using a laser resonance to enhance a transition probability of an electron-phonon coupling from the high energy level to a multi-phonon coupling level, so as to realize the emission and enhancement of breakthrough fluorescence spectrum and realize the radiation light oscillation, wherein the laser cavity includes an incident mirror, a folding mirror, a tuning element and an exit mirror arranged in sequence along an optical path direction, the laser gain medium is located between an incident mirror and a folding mirror in the laser resonator, and the tuning element is arranged in the laser cavity at a Brewster angle.

A method and a laser for breaking through the limitation of fluorescence spectrum on laser wavelength is disclosed. The method includes: exciting electrons to a high energy level by pump light, and suppressing an oscillation of radiation light by laser cavity coating, using a laser resonance to enhance a transition probability of an electron-phonon coupling from the high energy level to a multi-phonon coupling level, so as to realize the emission and enhancement of breakthrough fluorescence spectrum and realize the radiation light oscillation, wherein the laser cavity includes an incident mirror, a folding mirror, a tuning element and an exit mirror arranged in sequence along an optical path direction, the laser gain medium is located between an incident mirror and a folding mirror in the laser resonator, and the tuning element is arranged in the laser cavity at a Brewster angle.

An optical fiber mode stripper, a manufacturing method for an optical fiber mode stripper, and a laser are provided. The optical fiber mode stripper includes an optical fiber and fillers. The optical fiber is provided with a waveguide destruction region extending along a length direction of the optical fiber. A portion of the optical fiber in the waveguide destruction region includes a core and a cladding layer. The cladding layer is provided with recessed structures disposed at intervals along the length direction of the optical fiber and/or disposed at intervals circumferentially around the cladding layer. The fillers are filled in the recessed structures. The filler has a refractive index greater than a refractive index of the cladding layer.

An optical fiber mode stripper, a manufacturing method for an optical fiber mode stripper, and a laser are provided. The optical fiber mode stripper includes an optical fiber and fillers. The optical fiber is provided with a waveguide destruction region extending along a length direction of the optical fiber. A portion of the optical fiber in the waveguide destruction region includes a core and a cladding layer. The cladding layer is provided with recessed structures disposed at intervals along the length direction of the optical fiber and/or disposed at intervals circumferentially around the cladding layer. The fillers are filled in the recessed structures. The filler has a refractive index greater than a refractive index of the cladding layer.

A fiber laser apparatus includes: an amplification optical fiber that amplifies a laser beam; one or more pumping light sources that generate pumping light that is supplied to the amplification optical fiber; an output optical fiber including a first core that allows the laser beam amplified by the amplification optical fiber to propagate therethrough, and a first cladding having a refractive index lower than a refractive index of the first core and surrounding a circumference of the first core; a delivery fiber including a second core optically coupled to the first core of the output optical fiber, and a second cladding having a refractive index lower than a refractive index of the second core and surrounding a circumference of the second core; and a first housing unit that houses the amplification optical fiber and the output optical fiber therein.