Patent ID: 8295321

Claim:
A laser light source comprising: a main resonator configured so that a first reflection mirror and an output mirror are disposed so as to be opposed to each other with a laser medium placed therebetween; and an external resonator configured so that the output mirror and a second reflection mirror are disposed so as to be opposed to each other, which is optically coupled to the main resonator via the output mirror; wherein the second reflection mirror is configured such that it gives amplitude or phase variations to respective positions in the section of a light beam when the light is reflected, the second reflection mirror presents an amplitude or phase variation distribution, and determines a transverse mode of laser oscillation light based on the amplitude or phase variation distribution, and the laser light source further comprising a light beam diameter adjuster which is provided on the resonance light path in the main resonator or in the external resonator and adjusts the beam diameter of light incident on the second reflection mirror.