Patent ID: 7130321

Claim:
A laser, comprising: a traveling wave ring laser resonator; first, second, and third optically nonlinear crystals located in said ring resonator; said ring resonator including at least one gain-element generating fundamental radiation in said ring resonator, said fundamental radiation circulating through said first second and third optically nonlinear crystals in the sequence listed; said first optically nonlinear crystal arranged to convert a portion of said fundamental radiation to second-harmonic radiation; said second optically nonlinear crystal arranged to convert a portion of said second-harmonic radiation from said first optically nonlinear crystal into radiation having a converted frequency different from the frequency of said second-harmonic radiation; and wherein said third optically nonlinear crystal is arranged to convert at least a portion of a remaining portion of said second-harmonic radiation from said second optically nonlinear crystal back to fundamental radiation.