Highly efficient millijoule-level 3.5 µm MgO-doped periodically poled lithium niobate optical parametric oscillator

Abstract

We report a millijoule-level mid-infrared MgO-doped periodically poled lithium niobate (MgO:PPLN) optical parametric oscillator pumped by a 1.064 µm nanosecond laser. The maximum mid-infrared 3.5 µm idler output energy reached 3.65 mJ at the pump energy of 21 mJ, corresponding to a photon conversion efficiency of 57%. The wavelength tunabilities of the signal and idler outputs were also realized, with the continuous tuning ranges of 1.501 to 1.558 µm and 3.650 to 3.353 µm, respectively, by controlling the temperature of the MgO:PPLN crystal. The beam quality factor (M 2 ) of the mid-infrared idler output was measured to be <1.75.

Tunable 3 µm optical vortex parametric oscillator

“…The measured tuning curve was well fitted with the one simulated employing Sellmeier equations. 38) Further, the spectrum bandwidths of the pump and idler outputs were estimated to be ∼10 GHz (∼0.03 nm) and >80 GHz (∼2.4 nm), respectively, by measuring the temporal coherence functions [Fig. 4(c)].…”

“…Further power scaling of the 3-µm vortex laser system with a simple linear cavity will be possible only by the improvement of the pumping system. Note that the wavelength tuning range of the system will be further expanded by utilizing a PPLN crystal with multiple gratings 38) or a fan-out grating. 39) A higher-order vortex output generation will also be possible by employing the SLM for modulating the pump wavefront.…”

Near to Mid-Infrared (1.3–5 μm) Widely Tunable, High Power Picosecond Pulsed Laser

“…Nonlinear frequency conversion is perhaps the most commonly used method of wavelength converting laser sources. Some of the most utilized processes include second harmonic generation [8], sum frequency generation [9], OPO [10][11][12][13], optical parametric amplification (OPA) [14] and Raman scattering [15]. For the generation of long-wavelength laser fields, OPOs and OPAs are the most commonly used techniques.…”

Potassium titanyl arsenate based cascaded optical parametric oscillator emit at 2.5 µm derived by neodymium-doped yttrium lithium fluoride laser

“…18) The cascaded OPO in NCPM KTA pumped by neodymium-doped lasers could emit the laser wavelength ranging from 2.5 to 2.7 µm which can be applied in laser radar, atmospheric measurements, biomedical and medical applications. [19][20][21] Recently, our group reported a 2.6 µm laser from an intracavity pumped self-cascaded OPO based on NCPM KTA derived by Nd:YVO 4 laser at 1064 nm. An average output power of 445 mW was obtained under an incident diode pump power of 8.7 W. 22) The serious thermal lens effect of the Nd:YVO 4 crystal leaded to mode mismatch between the fundamental cavity and the OPO cavity, thus it exhibited lower output efficiency at high pump power for this self-cascaded OPO.…”