Patent ID: 8542435

Claim:
A doubly resonant optical parametric oscillator with achromatic phase-maintaining pump reflection comprising: a pump radiation source at a frequency f p , and comprising in the forward propagation direction of the pump radiation: a non linear crystal having a front face and a rear face, an achromatic mirror situated downstream of the rear face of the crystal, defining with a first mirror situated on the front face of the crystal, a first resonant cavity for the radiation signal at the frequency f s and with a second mirror situated upstream of the front face of the crystal, a second resonant cavity for the complementary radiation at the frequency f c , the two cavities, of respective optical lengths l s and l c , forming a doubly resonant resonator for a single pair of longitudinal signal and complementary modes, the pump radiation at the frequency f p makes through the crystal a forward path entering via the front face of the crystal and exiting via the rear face of the crystal, then, after reflection on the achromatic mirror, a backward path entering via the rear face of the crystal, the optical indices of which are respectively n s and n c at the signal f s and complementary f c frequencies, the crystal is wedged with its rear face inclined along a non zero angle α with respect to the direction x orthogonal to the direction z of propagation of the radiations, the crystal being moveable in the plane xz, wherein the crystal is moveable in translation in the plane xz along a direction inclined by a non zero angle b with respect to the direction x such that tg ⁢ ⁢ β = ( n c - 1 ) + R · ( n s - 1 ) R ⁢ tg ⁢ ⁢ α , with R = ( f s f c ⁢ l c l s ) , to modify simultaneously the respective optical lengths l s and l c of the two resonant cavities in a ratio such that the double resonance for a single pair of longitudinal signal and complementary modes is maintained, and as a result the values of the frequencies f s and f c are continuously tunable over a wide range.