Fabrication and spectral properties of Nd3+-doped yttrium lanthanum oxide transparent ceramics

Transparent 1 at% Nd3+:Y1.9La0.1O3 ceramics were fabricated with nanopowders prepared by carbonate coprecipitation method. The powder compacts were sintered in H-2 atmosphere at 1550 degrees C for 30 h. The Nd3+:Y1.9La0.1O3 ceramics display uniform grains of about 50 mu m and high transparency. The highest transmittance of the ceramics reaches 67%. The strongest absorption peak is in the wavelength of 820 nm with absorption cross section of 2.48 x 10(-20) cm(2). The absorption is still high at LD wavelength 806 nm with absorption cross section of 1.78 x 10(-20) cm(2) and broad full width at half maximum (FWHM) of about 6.3 nm. The strongest emission peak was centered at 1078 nm with large stimulated emission cross section of 9.63 x 10(-20) cm(2) and broad FWHM of about 7.8 nm. The broad absorption and emission bandwidth of Nd3+:y(1.9)La(0.1)O(3) transparent ceramics are favorable to achieve the miniaturized LD pumping apparatus and ultrashort modelocked pulse laser output, respectively. (c) 2007 Elsevier B.V. All rights reserved.

Room temperature efficient actively Q-switched Ho:YAP laser

We report on efficient actively Q-switched Ho: YAP laser double-pass pumped by a 1.91-mu m laser. At room temperature, when the incident pump power was 20.9 W, a maximum average output power of 10.9W at 2118 nm was obtained at the repetition rate of 10 kHz, and this corresponds to a conversion efficiency of 52.2% and a slope efficiency of 63.5%. Moreover, a maximum pulse energy of similar to 1.1 mJ and a minimum pulse width of 31 ns were achieved, with the peak power of 35.5 kW. (C) 2009 Optical Society of America

Laser-induced damage threshold of ZrO2 thin films prepared at different oxygen partial pressures by electron-beam evaporation

ZrO2, films were deposited by electron-beam evaporation with the oxygen partial pressure varying from 3 X 10(-3) Pa to I I X 10(-3) Pa. The phase structure of the samples was characterized by x-ray diffraction (XRD). The thermal absorption of the films was measured by the surface thermal lensing technique. A spectrophotometer was employed to measure the refractive indices of the samples. The laser-induced damage threshold (LIDT) was assessed using a 1064, nm Nd: yttritium-aluminium-garnet pulsed laser at pulse width of 12 ns. The influence of oxygen partial pressure on the microstructure and LIDT of ZrO2 films was investigated. XRD data revealed that the films changed from polycrystalline to amorphous as the oxygen partial pressure increased. The variation of refractive index at 550 nm wavelength indicated that the packing density of the films decreased gradually with increasing oxygen partial pressure. The absorptance of the samples decreased monotonically from 125.2 to 84.5 ppm with increasing oxygen partial pressure. The damage threshold, values increased from 18.5 to 26.7 J/cm(2) for oxygen partial pressures varying from 3 X 10(-3) Pa to 9 X 10(-3) Pa, but decreased to 17.3 J/cm(2) in the case of I I X 10(-3) Pa. (C) 2005 American Vacuum Society.

Microstructure and laser-induced damage threshold of ZrO2 coatings dependence on annealing temperature

ZrO2 coatings were deposited on different substrates of Yb:YAG and fused silica by electron beam evaporation. After annealed for 12 h at 673 and 1073 K, respectively, weak absorption of coatings was measured by surface thermal lensing (STL) technique, and then laser-induced damage threshold (LIDT) was determined also. The crystalline phase of ZrO2 coatings and the size of the crystal grain were investigated by X-ray diffraction. It was found that microstructure of ZrO2 coatings was dependent on both annealing temperature and substrate structure, and coatings containing monoclinic phases had higher damage threshold than others. Due to the strong absorption of Yb:YAG, damage threshold of coatings on Yb:YAG was much less than that on fused silica. (C) 2004 Elsevier B.V. All rights reserved.

Laser-induced damage threshold of ZrO2 thin films prepared at different oxygen partial pressures by electron-beam evaporation

ZrO2, films were deposited by electron-beam evaporation with the oxygen partial pressure varying from 3 X 10(-3) Pa to I I X 10(-3) Pa. The phase structure of the samples was characterized by x-ray diffraction (XRD). The thermal absorption of the films was measured by the surface thermal lensing technique. A spectrophotometer was employed to measure the refractive indices of the samples. The laser-induced damage threshold (LIDT) was assessed using a 1064, nm Nd: yttritium-aluminium-garnet pulsed laser at pulse width of 12 ns. The influence of oxygen partial pressure on the microstructure and LIDT of ZrO2 films was investigated. XRD data revealed that the films changed from polycrystalline to amorphous as the oxygen partial pressure increased. The variation of refractive index at 550 nm wavelength indicated that the packing density of the films decreased gradually with increasing oxygen partial pressure. The absorptance of the samples decreased monotonically from 125.2 to 84.5 ppm with increasing oxygen partial pressure. The damage threshold, values increased from 18.5 to 26.7 J/cm(2) for oxygen partial pressures varying from 3 X 10(-3) Pa to 9 X 10(-3) Pa, but decreased to 17.3 J/cm(2) in the case of I I X 10(-3) Pa. (C) 2005 American Vacuum Society.

Effect of metal contact's reflection on the effective coupling coefficient of second-order DFB laser diodes

For a second-order DFB-LD, the presence of a metal contact layer can reduce I-st-order radiation. Part of the reflected power is redistributed into guided modes and results in a variation of the effective coupling coefficient kappa(eff). In this paper, we study the effect of the Au top contact's reflection on the kappa(eff) of 2(nd)-order DFB lasers. (C) 2004 Wiley Periodicals, Inc.

Antiphase state in passively Q-switched Yb : YAG microchip multimode lasers with a saturable absorber GaAs

We report on recent experimental results of the spontaneous antiphase dynamics that occurs in a laser-diode-pumped multimode passively Q-switched microchip Yb:YAG (where YAG is yttrium aluminum garnet) lasers with a saturable absorber GaAs. We observe that the pulse sequence of the first mode characterized by one, two, and three pulses as a group and all the modes display an antiphase state as the pumping ratio rises. We modify the multimode rate equations to account for nonlinear absorption due to GaAs in the presence of spatial hole burning. We perform numerical simulations based on the proposed rate equations and reproduce the observed antiphase state of two and three active modes.

12 W high efficiency single frequency ring laser

Single-frequency output power of 12 W at 1064 nm is demonstrated. Pumped by a fiber-coupled diode laser, the Nd:YVO4 produces 58.6% of the slope efficiency with respect to absorbed pump power, and 52.7% of the optical-optical efficiency and nearly diffraction-limited output with a beam quality parameter of M-2 approximate to 1.11. To the best of our knowledge, this is the highest slope efficiency and optical-optical efficiency in single-frequency Nd:YVO4 ring laser. The slope efficiency of the single frequency laser is close to the limit of the efficiency. [GRAPHICS] output spectrum of the single-frequency Nd:YVO4 ring laser

A 20.1 W Solid-State Laser Pumped by 887 nm with High Efficiency and TEM00 Mode

High efficiency, TEM00 mode, high repetition rate laser pumped by 887 nm is reported. 20.1 W output laser emitting at 1064 nm is achieved in a 0.3 at % Nd-doped Nd:YVO4, which absorbs pumping light of 30.7 W at 887 nm. The opto-optic efficiency and the slope efficiency are 65.5 and 88.5%, respectively. The stable Q-switching operation worked well at 100 kHz and the beam quality is near diffraction-limit with M-2 factor measured as M-2 approximate to 1.2. And the pulse waveform is analyzed in this paper.

Spectroscopic properties of anisotropic absorption in a neodymium-doped YAlO3 laser crystal

Absorption spectra of YAlO3:Nd for the three crystallographic axes are investigated at room temperature, The spectral strengths indicate that the absorption coefficient of YAlO3:Nd is anisotropic. The anisotropy of the local electric field acting on the rare-earth ion in a laser crystal is considered, An extended Judd-Ofelt theory is applied to calculate the absorption cross sections and oscillator strengths of the electric-dipole transitions in the different principal directions. Three groups of the phenomenological parameters are derived from a least-squares-fitting procedure. We also analyze theoretically the anisotropy of the optical absorption of YAlO3:Nd crystal in detail. (C) 1997 American Institute of Physics.

Near-infrared luminescent mesoporous materials covalently bonded with ternary lanthanide [Er(III), Nd(III), Yb(III), Sm(III), Pr(III)] complexes

New near-infrared-luminescent mesoporous materials were prepared by linking ternary lanthanide (Er3+, Nd3+, Yb3+, Sm3+, Pr3+) complexes to the ordered mesoporous MCM-41 through a functionalized 1,10-phenanthroline (phen) group 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline. The resulting materials (denoted as Ln(hfth)(3)phen-M41 and Pr(tfnb)(3)phen-M41; Ln=Er, Yb, Nd, Sm; hfth = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dionate; tfnb = 4,4,4-trifluoro-1-(2-naphthyl)- 1, 3-butanedionate) were characterized by powder X-ray diffraction, N-2 adsorption/desorption, and elemental analysis. Luminescence spectra of these lanthanide-complex functionalized materials were recorded, and the luminescence decay times were measured. Upon excitation at the absorption of the organic ligands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide (Er3+, Nd3+, Yb3+, Sm3+, Pr3+) ions by sensitization from the organic ligands moiety. The good luminescent performances enable these NIR-luminescent mesoporous materials to have possible applications in optical amplification (operating at 1300 or 1500 nm), laser systems, or medical diagnostics.

Studies on extracting solutions of endohedral rare-earth metallofullerenes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Thirteen extracting solutions of rare-earth metallofullerenes containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb respectively have been investigated by means of matrix-assisted laser desorption/ionization time-of-night, mass spectrometry. The influences of the positive-ion/negative-ion mode, laser intensity, matrix and mass discrimination to the analytical results are studied, based on which the optimal analytical conditions have been determined. The results show that the extracting solutions contain large quantities of rare-earth metallofullerenes brs;des empty fullerenes, On the basis of comparing their relative intensities, the different structure stabilities and solubilities of metallofullerenes with different rare-earth metals encapsulated into the fullerene cages, as well as some possible reasons to those differences, are discussed.