Patent ID: 7991026
Filing Date: 2011-08-02
Classification: H01S

Abstract:
1. Optical apparatus comprising: first and second resonators having first and second portions with the first resonator portions being coaxial and the second portions separate; an OPS-structure located in the second portion of the first resonator; an arrangement for delivering optical pump radiation to the OPS-structure such that laser radiation having a fundamental wavelength circulates in the first resonator; a first optically nonlinear crystal located in the coaxial first portions of the first and second resonators and arranged for optical parametric division of a portion of the fundamental wavelength radiation into signal radiation and idler radiation portions, the signal radiation portion having a wavelength greater than the wavelength of the fundamental radiation and less than the wavelength of the idler radiation portion; an optical arrangement for directing the signal radiation into the second portion of the second resonator such that signal radiation circulates in the second resonator; a second optically nonlinear crystal located in the coaxial first portions of the first and second resonators and arranged for sum-frequency mixing circulating fundamental wavelength radiation and signal wavelength radiation to provide sum-frequency radiation; and wherein the fundamental wavelength of the OPS-laser radiation is selected such that the sum-frequency radiation has a wavelength between about 550 nanometers and 700 nanometers.