A laser arrangement, comprising: a pump source for providing optical pumping radiation; a first and a second cavity end mirror forming a resonant optical cavity; an optically pumpable gain material located in said resonant optical cavity, said gain material being capable of emitting fundamental coherent radiation at a fundamental wavelength when optically pumped by said pumping radiation; a birefringent, nonlinear element capable of converting the frequency of said fundamental radiation; a polarizing element structured and arranged to provide low losses for light of a predetermined polarization state oscillating within the resonant cavity; and a folding mirror defining a first and a second branch for said resonant optical cavity; wherein said polarizing element and said folding mirror are arranged on opposite sides of the birefringent, nonlinear element, and wherein the polarizing element is arranged between the birefringent, nonlinear element and one of the cavity end mirrors in a branch of the resonant optical cavity other than the branch containing the gain material; characterized in that the birefringent, nonlinear element is structured and arranged to convert the frequency of said fundamental radiation by quasi phase-matched nonlinear interaction, and wherein said nonlinear element is oriented with its optical axis rotated with respect to the wave emitted by the gain material, such that the wave emitted by the gain material can be described by a first component parallel to the optical axis of the nonlinear element and a second component orthogonal thereto, the nonlinear element further being designed for frequency conversion of light polarized parallel to said optical axis of the nonlinear element; and said polarizing element is oriented to introduce losses for the second component during a single pass of the fundamental wave through said polarizing element equal to the nonlinear losses experienced by the first component during a single pass through the nonlinear element. a pump source for providing optical pumping radiation; a first and a second cavity end mirror forming a resonant optical cavity; an optically pumpable gain material located in said resonant optical cavity, said gain material being capable of emitting fundamental coherent radiation at a fundamental wavelength when optically pumped by said pumping radiation; a birefringent, nonlinear element capable of converting the frequency of said fundamental radiation; a polarizing element structured and arranged to provide low losses for light of a predetermined polarization state oscillating within the resonant cavity; and a folding mirror defining a first and a second branch for said resonant optical cavity; wherein said polarizing element and said folding mirror are arranged on opposite sides of the birefringent, nonlinear element, and wherein the polarizing element is arranged between the birefringent, nonlinear element and one of the cavity end mirrors in a branch of the resonant optical cavity other than the branch containing the gain material; characterized in that the birefringent, nonlinear element is structured and arranged to convert the frequency of said fundamental radiation by quasi phase-matched nonlinear interaction, and wherein said nonlinear element is oriented with its optical axis rotated with respect to the wave emitted by the gain material, such that the wave emitted by the gain material can be described by a first component parallel to the optical axis of the nonlinear element and a second component orthogonal thereto, the nonlinear element further being designed for frequency conversion of light polarized parallel to said optical axis of the nonlinear element; and said polarizing element is oriented to introduce losses for the second component during a single pass of the fundamental wave through said polarizing element equal to the nonlinear losses experienced by the first component during a single pass through the nonlinear element.