ABSTRACT
We present a holmium-doped all-fiber master oscillator power amplifier (MOPA) system operating at 2108 nm targeting optical frequency conversion applications. The MOPA delivers pulses of 0.52 mJ energy at 10 kHz repetition rate after three amplification stages, with a close to square-shaped temporal profile of 50 ns duration, diffraction-limited beam quality and linear polarization. Challenges with achieving high gain and efficiency in the final amplification stage are discussed and attributed to quenching effects inferred from measurements of non-saturable absorption in the holmium fibers. Using this MOPA, we demonstrate a mid-IR conversion efficiency of 59% by direct pumping of a ZnGeP2 optical parametric oscillator.
ABSTRACT
A high-energy mid-infrared ZnGeP2 (ZGP) optical parametric oscillator (OPO) based on the nonplanar fractional-image-rotation enhancement resonator pumped by a 2.05 µm Ho3+:YLF laser is presented. Up to 120 mJ pulse energy in a rotationally symmetric beam is generated in the 3-5 µm wavelength range at 1 Hz repetition rate. Slope efficiencies of up to 78% are achieved with respect to the pump pulse energy incident onto the ZGP crystal. The OPO pulses have a duration close to 15 ns, corresponding to a maximum peak power of 8 MW. A measurement of M2 dependence on pump beam diameter is presented.
ABSTRACT
Mid-infrared (3-5 µm) pulses with high energy are produced using nonlinear conversion in a ZnGeP(2)-based master oscillator-power amplifier, pumped by a Q-switched cryogenic Ho:YLF oscillator. The master oscillator is based on an optical parametric oscillator with a V-shaped 3-mirror ring resonator, and the power amplifier is based on optical parametric amplification in large-aperture ZnGeP(2) crystals. Pulses with up to 212 mJ energy at 1 Hz repetition rate are obtained, with FWHM duration 15 ns and beam quality M(2) = 3.
ABSTRACT
We report 550 mJ pulses with 14 ns FWHM duration at 1 Hz repetition rate from a Q-switched cryogenic Ho:YLF oscillator pumped with 100 W in 35 ms by a Tm:fiber laser. The laser has a confocal unstable resonator with a graded-reflectance output coupler, resulting in a beam quality of M(2) = 1.5. Pulse energies of 416 and 343 mJ were obtained at 10 and 20 Hz repetition rate, respectively.
ABSTRACT
A compact and versatile femtosecond mid-IR source is presented, based on an optical parametric oscillator (OPO) synchronously pumped by a commercial 250-MHz Er:fiber laser. The mid-IR spectrum can be tuned in the range 2.25-2.6 µm (signal) and 4.1-4.9 µm (idler), with average power from 20 to 60 mW. At 2.5 µm a minimum pulse duration of 110 fs and a power of 40 mW have been obtained. Active stabilization of the OPO cavity length has been achieved in the whole tuning range.
Subject(s)
Amplifiers, Electronic , Lasers, Solid-State , Oscillometry/instrumentation , Equipment Design , Equipment Failure AnalysisABSTRACT
A mid-infrared synchronously pumped optical parametric oscillator pumped by a femtosecond erbium-doped fiber laser is demonstrated and characterised. The idler is tunable from 3.7-4.7 µm, with a maximum average power of 37 mW and a pulse length of â¼ 480 fs at 4 µm. We compare the experimental results with numerical results based on an extensive simulation model.
ABSTRACT
We report on a ZnGeP(2)-based optical parametric oscillator (OPO) with 22 W of output power in the 3-5 µm range and a beam quality factor M(2) ≈1.4. The OPO uses a novel V-shaped 3-mirror ring resonator that allows two passes of the beams through the same nonlinear crystal. The pump is a 39 W hybrid Tm:fiber laser/Ho:YAG laser.
