Abstract: A laser oscillator for improving efficiency of conversion from solar rays to laser beams is provided. The laser oscillator includes: a laser medium 31 excited by solar rays S to output laser beams; an output mirror 35 having a concave surface 35a opposed to an output end of the laser medium 31; and a light guide 20 having a reflector 22 extending from the output end of the laser medium 31 towards the outside of the laser medium 31 and reflecting the solar rays Sf to guide them to the laser medium 31.

Abstract: Object: To provide a solar light pumped laser and a cooling method of a solar light pumped laser. Means for Solving the Problems: A solar light pumped laser performing laser oscillation by pumping a laser medium with solar light, the solar light pumped laser including, a laser medium 12, a container device 14 that supports the laser medium 12 therein, the container device 14 being provided with a focusing optical element 22 for irradiating solar light focused along the laser medium 12, while retaining cooling liquid in a space between the laser medium 12 and the container device 14, and additionally, a pair of optical reflection elements (16, 18) arranged adjacent to the opposing ends of the laser medium. An end of the container device 14 has Brewster's angle. Further, the cooling liquid according to the present invention contains water functioning as an optical medium to form a water lens simultaneously with cleaning the focusing optical element 22.

Abstract: An object of the present invention is to provide an extreme ultraviolet light source target which can emits extreme ultraviolet light with high emission efficiency. A solid target made of heavy metal or heavy-metal compound and having a density 0.5 to 80% that of the crystal density is used. When the target is irradiated with a laser beam, plasma of the heavy metal contained in the target is generated, and extreme ultraviolet light having a predetermined wavelength which corresponds to the kind of the heavy metal is emitted from the plasma. When the density of the target is made to be smaller than the crystal density as described above, space distribution of the density of the generated plasma can be controlled, and the region in which plasma absorbs energy of the laser beam overlaps the region in which the plasma emits the extreme ultraviolet light. Thus, emission efficiency can be improved, preventing energy loss.

Abstract: A solar light pumped laser performing laser oscillation by pumping a laser medium with solar light, the solar light pumped laser including, a laser medium 12, a container device 14 that supports the laser medium 12 therein, the container device 14 being provided with a focusing optical element 22 for irradiating solar light focused along the laser medium 12, while retaining cooling liquid in a space between the laser medium 12 and the container device 14, and additionally, a pair of optical reflection elements (16, 18) arranged adjacent to the opposing ends of the laser medium. An end of the container device 14 has Brewster's angle. Further, the cooling liquid according to the present invention contains water functioning as an optical medium to form a water lens simultaneously with cleaning the focusing optical element 22.

Abstract: An object of the present invention is to provide an extreme ultraviolet light source target which can emits extreme ultraviolet light with high emission efficiency. A solid target made of heavy metal or heavy-metal compound and having a density 0.5 to 80% that of the crystal density is used. When the target is irradiated with a laser beam, plasma of the heavy metal contained in the target is generated, and extreme ultraviolet light having a predetermined wavelength which corresponds to the kind of the heavy metal is emitted from the plasma. When the density of the target is made to be smaller than the crystal density as described above, space distribution of the density of the generated plasma can be controlled, and the region in which plasma absorbs energy of the laser beam overlaps the region in which the plasma emits the extreme ultraviolet light. Thus, emission efficiency can be improved, preventing energy loss.