Optical oscillator, method for designing optical oscillator, and laser device

A laser device comprising:

• an optical oscillator, wherein the optical oscillator comprises:
• a first reflection part configured to reflect light of a first wavelength;
• a laser medium excited by excitation light of a second wavelength different from the first wavelength and configured to emit light of the first wavelength;
• a second reflection part disposed on a side opposite to the first reflection part with respect to the laser medium and configured to form an unstable resonator configured to output annular laser light of the first wavelength together with the first reflection part;
• and
• a saturable absorption part disposed on the side opposite to the first reflection part with respect to the laser medium and of which a transmittance increases with absorption of light of the first wavelength;
• and
• an excitation light supply part configured to output the excitation light supplied to the laser medium, wherein,
• when an inner diameter of the annular laser light is indicated by di (mm), and an outer diameter is indicated by do (mm), and do/di is a magnification m, they magnification m is larger than 21/2,
• when a power of the excitation light is 1.5 kW or more and 12 kW or less, the magnification m is 1.44 or more and 4.01 or less,
• when a power of the excitation light is 3 kW or more and 12 kW or less, the magnification m is 1.47 or more and 5.1 or less, or
• when a power of the excitation light is 6 kW or more and 12 kW or less, the magnification m is 1.50 or more and 6.82 or less.