Alexandr A Kaminskii

72 W Nd:Y3Al5O12 ceramic laser

A high-power continuous-wave polycrystalline 1% Nd:Y{sub 3}Al{sub 5}O{sub 12} (Nd:YAG) ceramic rod laser was demonstrated. With 290 W/808 nm laser diode pumping, cw laser output of 72 W was obtained at 1064 nm. The optical-to-optical conversion efficiency is 24.8%. Thermally induced birefringence properties of Nd:YAG ceramic was also investigated. {copyright} 2001 American Institute of Physics.A high-power continuous-wave polycrystalline 1% Nd:Y3Al5O12 (Nd:YAG) ceramic rod laser was demonstrated. With 290 W/808 nm laser diode pumping, cw laser output of 72 W was obtained at 1064 nm. The optical-to-optical conversion efficiency is 24.8%. Thermally induced birefringence properties of Nd:YAG ceramic was also investigated.

High efficiency nanosecond Raman lasers based on tetragonal PbWO4 crystals

Abstract We report on laser action in linear and ring Raman oscillators based on novel χ (3) -active PbWO 4 crystals with scheelite structure ( ω R =901 cm −1 ). These resonators are pumped by the fundamental and the second harmonic wavelengths, respectively, of a Q-switched Nd 3+ :Y 3 Al 5 O 12 laser. In these preliminary measurements, conversion efficiencies as high as 20% are observed. To our knowledge, this is the first such demonstration of Raman lasing in lead tungstate in the nanosecond regime. Raman lasers based on PbWO 4 are very promising for several applications, including the generation of wavelengths in the uv (in conjunction with other nonlinear processes) for ozone differential absorption lidar. This material has optical transparency from ≈0.33 to ≈5.5 μm, making it also potentially useful for trace gas detection in the infrared. Furthermore, it has a high damage threshold and is not hydroscopic. Some new data on picosecond high-order Stokes and anti-Stokes generation are also presented. In particular, our SRS experiments with a 1-μm Nd 3+ :Y 3 Al 5 O 12 pump laser demonstrate multiple anti-Stokes emission up to the 10th component with λ ASt10 =0.5433 μm.

Efficient Picosecond PbWo/sub 4/ And Two-wavelength KGd(Wo/sub 1/)/sub 2/ Raman Lasers In The IR And Visible

A mode-locked Nd: YAG laser at 1064 nm generates stimulated Raman scattering inside the laser cavity as well as in an external cavity. We optimized the output power in the external cavity arrangement using a dielectric output mirror with 22% transmission. The spatial beam profile, input/output energy characteristics, and temporal emission distribution were studied. Raman laser action was achieved with PbWO 4 at λ = 1176 nm and with KGd(WO 4 ) 2 at both = 1159 nm and λ = 1177 nm. The conversion efficiencies reach 70%. The two lines in KGW are generated separately by rotating around the crystal b axis oriented parallel to the beam direction. All Raman laser wavelengths were converted to the yellow spectral region by second harmonic generation in LBO.

Femtosecond continuously tunable second harmonic generation over the entire-visible range in orthorhombic acentric Gd2(MoO4)3 crystals

Second harmonic generation over the entire visible range in Nd3+ doped and undoped Gd2(MoO4)3 crystals under ultrashort hypercontinuum pumping is presented. The continuous tuning ranges from 487 to 790 nm in a single crystal.

Observation of stimulated Raman scattering in Y3Al5O12 single crystals and nanocrystalline ceramics and in these materials activated with laser ions Nd3+ and Yb3+

High-order Raman parametric generation was excited in the visible and near-IR regions on the Stokes and anti-Stokes lines of Y3Al5O12 single crystals and nanocrystalline ceramics. All generation components, as well as the χ(3)-active vibrational modes of these materials, were identified. In connection with the extensive use of the Nd3+-and Yb3+-doped Y3Al5O12 crystals and, in recent years, nanocrystalline Y3Al5O12: Nd3+ ceramics in laser physics and quantum electronics, the applied aspect of the observed nonlinear properties of these materials is outlined.

Spectroscopic and laser properties of Er3+-doped monoclinic BaY2F8 single crystals

The luminescence and absorption properties of Ba(Y1−xErx)2F8 (x=0.001, 0.01, 0.05, 0.1, 0.2 and 0.3) and the Er3+-ion decay kinetics of luminescent transitions from three initial laser states, the4S3/2,4F.9/2 and4I11/2 manifolds, were measured. The crystal-field splitting schemes for allJ-manifolds which are involved in (J →J′)-luminescence transitions and stimulated emission parameters of Er3+ -ions in BaY2F8 were determined. A comparison of laser powers and efficiencies of BaY2F8 and Y3Al5O12, Lu3Al5O12 and LiYF4 single crystals doped with Er3+-ions shows the similar performance of these materials.

Spectroscopic investigation of the chromium-doped LiNbGeO5 laser crystal

Abstract Polarized absorption and emission spectra, and temperature dependences of the fluorescence lifetimes and intensities for the chromium-doped LiNbGeO5 laser crystal are presented. Crystal symmetry and comparison with the infrared fluorescence properties of the Cr-doped Mg2SiO4 and Y3Al5O12 laser crystals seem to identify the active center as a Cr4+ ion in a tetrahedral site.

Orthorhombic (LiNbGeO5): efficient stimulated Raman scattering and tunable near-infrared laser emission from chromium doping

Abstract The structural, optical, spectroscopic, and laser properties of pure and chromium-doped lithium–niobium germanate (LiNbGeO 5 ) single crystals are discussed in this paper. Efficient stimulated Raman scattering (SRS), investigated with the one-micron fundamental and second harmonic wave of a picosecond Nd 3+ :Y 3 Al 5 O 12 laser, reveals the potential of this new cubic non-linear susceptible ( χ (3) ) optical material for realizing effective solid state Raman shifters. The data are analyzed and compared with spectroscopic data from spontaneous Raman scattering. Pulsed tunable laser action of chromium-doped LiNbGeO 5 crystals was demonstrated in the spectral range between 1.3 and 1.52 μ m at cryogenic temperature and around 1.4 μ m at room temperature. Due to its excellent crystalline and optical properties, LiNbGeO 5 is a promising material for tunable near-infrared lasers with integrated frequency converters.

Excited state absorption around 1060 nm of Nd3+ ions in Ba2NaNb5O15 crystal

Abstract The Judd–Ofelt intensity parameters of Nd3+ ions in the nonlinear Ba2NaNb5O15 crystal have been determined, presenting values of Ω 2 =1.91×10 −20 , Ω 4 =2.61×10 −20 and Ω 6 =2.36×10 −20 cm2. These values were used to calibrate the excited state excitation measured around the main laser radiation at 1060 nm ( 4 F 3/2 → 4 I 11/2 channel) in terms of absorption cross-section units (cm2). The experimental results, using a two-beam experiment, show a low value of the excited state absorption cross-section (

Nd3+ centres in highly neodymium doped LaBGeO5 crystals

Abstract Site selective spectroscopy has been used to detect the different Nd3+ centers in the La1-XNdxBGeO5 system as Nd concentration level is increased from 0.2 to 10 at%. For the highest concentration the presence of two Nd3+ centers with very different crystal field was detected. Both types of centers are correlated with the two polymorphic phase, LaBGeO5 and NdBGeO5, with a different space group which coexist in the host for these high doping level.