A polarization-maintaining (PM) pulsed three-stage master oscillator power amplifier (MOPA) emitting at 2047 nm is reported, generating 19.8W of output power (396 μJ pulse energy) for a 50 ns pulse width at a repetition rate of 50 kHz. The output signal is linearly polarized and a diffraction limited beam quality is achieved. This MOPA laser is used to pump a doubly resonant ZnGeP2 (ZGP) optical parametric oscillator (OPO) in a linear cavity. A mid-IR output power of 8.1W, accordingly 162 μJ of pulse energy, and a conversion efficiency of 44 % are obtained in the 3-5 μm band.
We report on an actively Q-switched high-pulse-energy Ho3+:YAG laser in-band pumped by a Tm3+-doped fiber laser, both operated at room temperature. The Ho3+:YAG active medium inside a plane-plane cavity is pumped using a commercial Tm3+-doped fiber laser at 1908 nm from one side. In continuous operation a maximum power of 20.1 W with a slope efficiency of 45.1%, central wavelength of 2090 nm and a beam quality factor M2 below 1.5 were achieved. Q-switched operation was achieved using a Brewster-cut acousto-optic modulator (AOM) based on crystalline Quartz. During Q-switching the incident power was kept stable at 47 W to obtain an M2 of 1.3 and a stable thermal lens inside the laser crystal. With the variation of the repetition frequency a lower limit of the quasi-continuous pulsed regime was investigated and measured to be approximately 3 kHz. The maximum pulse energy in Q-switching operation was achieved with a repetition frequency of 700 Hz leading to an energy of 15 mJ at 12.1 ns pulse width, corresponding to a peak power of 1.2 MW. The laser showed no sign for a loss of performance during many hours of testing. Using this laser as a pump source for a double resonant OPO, a maximum mid-infrared output power of 6.3 W could be achieved at a repetition frequency of 2 kHz, accompanied by a low threshold power of 1.6 W and a slope efficiency of 49.2%.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.