摘要 |
A tunable narrowband optical parametrical oscillator (OPO) is excited in pulsed fashion to generate tunable narrowband radiation. A wavelength selective means (T, G) disposed outside the resonant cavity (M3, M4) of the optical parametrical oscillator reduces the bandwidth of the OPO radiation generated. A pumping pulse is divided by a beam splitter (DM1) into at least two partial pulses, and the delay between the two partial pulses is adjusted by means of a delay distance (D) in such a mannner that the first partial pulse will pump the crystal of the optical parametrical oscillator, part of the OPO radiation thus generated passing through the wavelength selective means which is arranged outside the resonant cavity, being coupled back into the resonant cavity, and passing through the crystal (C) once again when the second partial pulse (2) pumps the crystal (C).
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