Abstract: A laser output measuring apparatus in which an optical separator is disposed in a position that is rotated by a predetermined angle about an optical axis of a laser beam converged by a lens, and further rotated by a predetermined angle about the optical axis of the laser beam and a straight line perpendicular to an incident surface of the laser beam.

Abstract: A laser medium 21 is shaped like a plate and has a waveguide structure in a direction of the thickness of a surface thereof perpendicular to the optical axis thereof. A nonlinear material 31 is placed on the optical axis of the laser medium 21 close to the laser medium 21 and has a waveguide structure in the same direction as that of the waveguide structure of the laser medium 21. A ¼ wavelength plate 41 is placed close to one of surfaces, which are perpendicular to the optical axis, of the nonlinear material 31, the one being opposite to a surface close to the laser medium 21.

Abstract: Provided is a passively Q-switched element or the like, which enables mode selection without increasing the number of components in a resonator in a Q-switched pulse laser or the like that oscillates in a great number of high-order modes and which is also applicable to a waveguide type laser in which a mode cannot be controlled spatially. By combining a saturable absorber (2) with a transparent material (3) which is transparent to a laser oscillation wavelength or the like, a passively Q-switched element having a mode selection function and a passively Q-switched laser device in which a passively Q-switched element has a mode selection function, and a planar waveguide type passively Q-switched element and passively Q-switched laser device are provided.

Abstract: A laser medium 21 is shaped like a plate and has a waveguide structure in a direction of the thickness of a surface thereof perpendicular to the optical axis thereof. A nonlinear material 31 is placed on the optical axis of the laser medium 21 close to the laser medium 21 and has a waveguide structure in the same direction as that of the waveguide structure of the laser medium 21. A ¼ wavelength plate 41 is placed close to one of surfaces, which are perpendicular to the optical axis, of the nonlinear material 31, the one being opposite to a surface close to the laser medium 21.

Abstract: Provided is a passively Q-switched element or the like, which enables mode selection without increasing the number of components in a resonator in a Q-switched pulse laser or the like that oscillates in a great number of high-order modes and which is also applicable to a waveguide type laser in which a mode cannot be controlled spatially. By combining a saturable absorber (2) with a transparent material (3) which is transparent to a laser oscillation wavelength or the like, a passively Q-switched element having a mode selection function and a passively Q-switched laser device in which a passively Q-switched element has a mode selection function, and a planar waveguide type passively Q-switched element and passively Q-switched laser device are provided.

Abstract: A laser output measuring apparatus in which an optical separator is disposed in a position that is rotated by a predetermined angle about an optical axis of a laser beam converged by a lens, and further rotated by a predetermined angle about the optical axis of the laser beam and a straight line perpendicular to an incident surface of the laser beam.

Abstract: A laser output measurement mechanism includes a light splitter that is disposed in a state rotated by a predetermined angle about an optical axis of laser light incident thereon, and that reflects a part of the laser light according to a Fresnel reflectivity that depends on a polarization direction and an incident angle of the laser light at a reflection surface thereof, and a light detector that measures an intensity of the laser light reflected by the light splitter.