Intracavity optical parametric oscillator based on GTR-KTP pumped by diode-side-pumped acousto-optically Q-switched Nd:YAG laser.

With a non-critically phase-matched high gray-trace resistance KTP (GTR-KTP) crystal, a high-power intracavity optical parametric oscillator (IOPO) emitting at the wavelength of 1.5 μm and pumped by a diode-side-pumped acousto-optically Q-switched Nd:YAG laser is experimentally demonstrated. At the frequency repetition rate of 6 kHz, the maximum average power of 6.36 W at signal wavelength 1570 nm with a pulse width of 9.94 ns is obtained from IOPO based on GTR-KTP, corresponding to a peak power of 107 kW and a single-pulse energy of 1.06 mJ, respectively. We have compared the GTR-KTP IOPO with common KTP IOPO using the same scheme. At the same cavity design, frequency repetition rate and pump condition, only 5.42 W average output power with pulse width 13.82 ns is obtained from IOPO based on common KTP. Besides the higher output power, the output stability of GTR-KTP IOPO is much better than that of common KTP OPO. The output instability of GTR-KTP IOPO is 0.83% versus 6.7% of the common KTP IOPO. [ABSTRACT FROM AUTHOR]