A Faraday isolator based on a new magneto-optical medium, TSAG (terbium scandium aluminum garnet) crystal, has been constructed and investigated experimentally. The device provides an isolation ratio ...of more than 30 dB at 500 W laser power. It is shown that this medium can be used in Faraday isolators for kilowatt-level laser powers.
The fabrication of transparent Sc2O3 ceramics by hot pressing of self-propagating high-temperature synthesized powders was developed. The effect of lithium fluoride aid and calcination temperature on ...the powders properties was investigated. After calcination at 1100 °C, uniformly shaped Sc2O3 nanopowders with a primary particle size of less than 50 nm were obtained. Using the prepared powders doped with LiF fully dense optical quality Yb:Sc2O3 transparent ceramics were fabricated by hot pressing. The in-line transmittance of the sample reached 78% at a wavelength of 800 nm. Laser generation with a maximum efficiency of 24% was achieved using a 2% Yb: Sc2O3 sample.
•Pure and LiF-doped Scandia nanopowders were prepared by SHS method.•LiF aid promotes hot pressing (HP) process and leads to formation of pore-free Sc2O3 ceramics.•The transmission and luminescence spectra of the Yb:Sc2O3 ceramics were measured.•Laser generation with efficiency of 24% was achieved on the prepared 2%Yb:Sc2O3 sample.
Yb:YAG Slab Laser Amplifier Kuzin, D. A.; Starobor, A. V.; Kuznetsov, I. I. ...
Bulletin of the Lebedev Physics Institute,
07/2024, Letnik:
51, Številka:
Suppl 3
Journal Article
Recenzirano
A laser amplifier based on an active element in the shape of a Yb:YAG slab is developed. It combines the propagation of an amplified elliptical beam without internal reflections, the use of ...high-brightness diode pump channel combining, and a heat sink made of silicon carbide. Its laser characteristics and factors limiting the output pulse energy are studied. It is shown that the application of an active element with gradient doping ensures stable operation of the laser head at pump powers of ∼0.5 kW. The use of signal radiation diverging along one axis compensates for the effect of reducing the output cross section of the amplified beam; as a result, a gain of
G
= 4 is ensured with a beam quality factor
M
2
< 1.4.
A Faraday isolator with compensation of thermally induced depolarization outside magnetic field was implemented for the first time on TGG ceramics. Stable isolation ratio of 38 dB in steady-state ...regime at a laser power of 300 W was demonstrated in experiment. Theoretical estimates show a feasibility of a device that would provide an isolation ratio higher than 30 dB up to laser power of 2kW.
Thermal lens, absorption coefficient for 1076 nm radiation and spectral dependence of the Verdet constant were measured in PrF3, EuF2.11 and Na0.38Ho0.62F2.24 crystals for magneto-optical ...applications. As evaluated in the 400–1310 nm wavelength range, the Verdet constant of the EuF2.11 crystals is ~30% higher than that of the TGG crystals, an at the wavelength of 1557 nm it is 100% higher. The Verdet constant of PrF3 crystals is ~5% lower than in TGG throughout the studied wavelength range. Na0.38Ho0.62F2.24 crystals have the lowest (among the studied crystals) value of the Verdet constant that is 50–80% lower than in TGG.
The thermal lens was measured by the phase-shift interferometry technique and has the sign opposite to that of the TGG lens for all considered crystal. The thermo-optical constant P and the dependence of the thermal lens on the absorbed power were calculated. It is shown that the optical power of thermal lens in PrF3, EuF2.11 and Na0.38Ho0.62F2.24 at equal absorbed laser power is, respectively, 1.3, 1.7 and 1.8 times higher than in TGG.
•Magneto-active EuF2.11, PrF3, and Na0.38Ho0.62F2.24 fluorides with a wider transparency region than TGG were studied.•The Verdet constant dispersion in EuF2.11, PrF3, and Na0.38Ho0.62F2.24fluorides was measured.•The thermal lens in magneto-active EuF2.11, PrF3, and Na0.38Ho0.62F2.24 fluorides was measured.•Thermal lens in the fluoride crystals is negative (defocusing).•With equal absorbed power the thermal lens in these crystals will be 1.7, 1.3 and 1.8 times higher than in TGG, respectively.
This work describes improvement of the magnetic trap and beam-formation system of the GISMO (Gas-Dynamic Ion Source for Multipurpose Operation) electron-cyclotron-resonance ion source for its ...application as a proton injector, which is an integral part of the linear accelerator of a compact neutron source. The magnetic trap is improved and now uses an open design consisting of permanent magnets based on a Nd–Fe–B alloy. This design is optimized to accommodate the extraction system in the part of the plasma chamber with a larger inner diameter compared to the GISMO source. Then, the three-electrode beam-formation system is optimized. The design parameters of the system are developed in such a way that an additional solenoid-shaped magnetic lens can effectively produce a proton beam with a small divergence at the output. Computer simulation proves that this magnetic trap and the extraction system can be used as part of a proton injector for the DARIA project. The next steps in the construction of a proton source are discussed.
The quality of surface treatment of different laser materials has been studied aimed at designing composite elements. We have shown that flatness of samples should be no worse than λ/10 and roughness ...no more than 1.0 nm. Characteristics of ion-beam etching were found that cause no roughness degradation: Ar ions,
E
ion
= 800 eV, and grazing angle θ = 5°. Ytterbium-doped yttrium aluminum garnet composite elements (Yb:YAG), along with a terbium gallium garnet (TGG) magnetoactive crystal with sapphire monocrystals, have been designed.
200 TW peak power has been achieved experimentally using a Cr:forsterite master oscillator at 1250 nm, a stretcher, three optical parametrical amplifiers based on KD*P (DKDP) crystals providing 14.5 ...J energy in the chirped pulse at 910 nm central wavelength, and a vacuum compressor. The final parametrical amplifier and the compressor are described in detail. Scaling of such architecture to multipetawatt power is discussed.
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