CC BY
21LS-I-5
High Efficiency In-Band Fiber-Laser Pumped 2-um Lasers Based on Tm-doped Ceramics and Crystals and Mid-IR Conversion of Their Radiation
O.L. Antipov
Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod 603155, Russia
antipov@ipfran. ru
Solid-state lasers based on Tm-doped materials and operating at wavelengths near 2.0 ^m have a variety of applications in medicine, materials processing, environmental monitoring and pumping of lasers or mid-IR optical parametric oscillators (OPOs) [1]. Specifically, the high-power and high-pulse energy 2-um Q-switched lasers are promising pump sources for the mid-IR lasers based on Cr2+ ions and OPOs. The in-band pumping of a 3H6-3F4 Tm3+-ion transition enables the high-efficiency and high-power operation of Tm3+-doped lasers at 1900-2100 nm with a low quantum defect [2-4].
This report gives an overview of the recent studies of Tm-doped solid-sate lasers based on Tm3+:Lu2O3 or Tm3+:Y2O3 ceramics and Tm3+:YAP crystals in-band pumped by a fiber laser at 1670 nm and their frequency conversion to the mid-IR in Cr-doped crystals (Cr2+:ZnSe or Cr2+:CdSe) and mid-IR OPOs based on periodically poled structures (MgO:LiNbO3 or KTA) or ZnGeP2 crystals [5,6].
Two cavity configurations of the solid-sate lasers based on Tm3+:Lu2O3 and Tm3+:Y2O3 ceramics or Tm3+:YAP crystals were studied: a two-mirror linear configuration or a three-mirror L-shaped cavity configuration. The Raman-shifted Er-fiber laser at 1670 nm with the CW output of up to 50 W was used as an end-pumping source in both cavity configurations. The high efficiency and high average power lasing at 1890-2080 nm was achieved in the CW or Q-switched regimes. A repetitively-pulsed Q-switched operation was obtained by using the acousto-optical modulators in a linear cavity or by inserting the Cr2+:ZnSe saturable absorbers into the output leg of an L-shaped cavity.
The Tm3+:Lu2O3 ceramic laser output was used to pump the Cr-doped single- or poly-crystals (Cr2+:ZnSe or Cr2+:CdSe). A high conversion efficiency to 2300-2600 nm was achieved in the Cr2+:ZnSe laser both in the CW and repetitively-pulsed regimes, while a longer-wavelength 2600-2800 nm output was demonstrated in the single-crystalline Cr2+:CdSe laser.
Finally, the mid-IR frequency conversion of Tm3+:YAP was achieved in OPOs based on periodically poled MgO:LiNbO3 or KTA. The Tm3+:Lu2O3 ceramic lasers were used as the pump sources for the mid-IR OPOs based on the ZNGeP2 crystals or the periodically poled MgO:LiNbOs structures.
References:
[1] K. Scholle, S. Lamrini, P. Koopmann, P. Fuhrberg in Frontiers in Guided Wave Optics and Optoelectronics (Croatia, InTech, 2010).
[2] O. Antipov, A. Novikov, S. Larin, I. Obronov, "Highly efficient 2 ^m CW and Q-switched Tm3+: Lu2O3 ceramics lasers in-band pumped by a Raman-shifted erbium fiber laser at 1670 nm," Opt. Letters, v. 41, 2298-301 (2016).
[3] O.L. Antipov Yu.A. Getmanovskiy, A.A. Dobrynin, H. T. Huang, D.Y. Shen, J. Wang,S.S. Balabanov, "High-efficiency CW and passively Q-switched operation of a 2050 nm L-shaped Tm3+:Y2O3 ceramic laser in-band fiber-laser pumped at 1670 nm," Applied Physics B, v. 127, 77(7) (2021)
[4] O.L. Antipov, Yu.A. Getmanovskiy, A.A. Dobrynin, et al, "Low-Quantum-Defect CW and Q-Switched Operation of a Tm3+:YAP Laser with the In-Band Fiber-Laser Pumping," in Technical digest of CLEO'Europe 2021, paper CA-P.17.
[5] O.L. Antipov, I.D. Eranov, M.P. Frolov, et al, "2.92 ^m Cr2+:CdSe single crystal laser pumped by a repetitively pulsed Tm3+: Lu2O3 ceramics laser at 2.066 ^m," Laser Physics Letters, v. 12, N4, 045801 (2015).
[6] D.B. Kolker, O.L. Antipov, S.V. Larin, L.I. Isaenko, V.N. Vedenyapin, A.R. Ahmatkhanov, V.Ya. Shur, "Mid-IR optical parametric oscillator based on periodically polled LiNbO3 pumped by Tm3+:Lu2O3 ceramic laser," Atmospheric and Oceanic Optics, v. 32, N6, 724-729 (2019).
