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Wyszukujesz frazę "Ryba-Romanowski, W." wg kryterium: Autor


Wyświetlanie 1-11 z 11
Tytuł:
Disordered Nd-Doped Crystals for Diode Pumping
Autorzy:
Ryba-Romanowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1929796.pdf
Data publikacji:
1993-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.45.+h
78.55.Hx
Opis:
Some interest has been directed recently to neodymium doped crystals with strong inhomogeneous broadening of absorption bands which are believed to be better suited for diode pumping than the crystals with ordered lattice. The disordered Nd-doped crystals may be obtained in two ways. The first one is to introduce a structural disorder in ordered lattice by substituting partially one or more cations by cations with different charges. Alternatively, the compounds with inherently disordered structure are synthesized and doped with Nd. We consider two wide families of compounds of general formulae ABC$\text{}_{3}$O$\text{}_{7}$ and ABCO$\text{}_{4}$ where A stands for Ca, Sr, Ba, B is Y or rare earth and C stands for Ga or Al. Both the families form the crystals with inherently disordered structure and can accept an appreciable amount of Nd. Results of structural and spectroscopic investigations are used to determine material's parameters relevant to laser performance. Comparison of several disordered crystals is made and their suitability for diode pumping is discussed.
Źródło:
Acta Physica Polonica A; 1993, 84, 5; 945-952
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Methods in Characterization of HTSC Thin Film Substrates
Autorzy:
Ryba-Romanowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1964242.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
42.70.Hj
Opis:
Short overview of optical methods which proved to be useful in the characterization of HTSC thin film substrates is presented. Preliminary tests in polariscopic arrangements, interferometric measurements, optical absorption and emission spectroscopy reveal macroscopic deficiencies of the crystal. Intentionally introduced impurity ions serve as probes of a local strength and symmetry of the crystal field. Results of optical study of SrLaGaO$\text{}_{4}$ and SrLaAlO$\text{}_{4}$ crystals are presented and discussed.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 135-138
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Material Parameters Characterizing the Performance of Flashlamp Pumped BaLa$\text{}_{1-x}$Nd$\text{}_{x}$Ga$\text{}_{3}$O$\text{}_{7}$ Laser
Autorzy:
Ryba-Romanowski, W.
Gołąb, S.
Berkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1887344.pdf
Data publikacji:
1991-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.60.-b
Opis:
Physical properties of optically uniaxial BaLa$\text{}_{1-x}$Nd$\text{}_{x}$Ga$\text{}_{3}$O$\text{}_{7}$ crystals have been investigated. Specific heat, thermal expansion coefficients, thermal diffusivity, Young modules and Poisson ratios of the crystal have been determined. Basing upon these parameters and the available spectral data the operating conditions for lasers employing rods made of BaLa$\text{}_{1-x}$Nd$\text{}_{x}$Ga$\text{}_{3}$O$\text{}_{7}$ have been defined.
Źródło:
Acta Physica Polonica A; 1991, 79, 4; 501-506
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Temperature on Refractive Indices of BaLaGa$\text{}_{3}$O$\text{}_{7}$ and SrLaGa$\text{}_{3}$O$\text{}_{7}$
Autorzy:
Ryba-Romanowski, W.
Gołąb, S.
Berkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1928265.pdf
Data publikacji:
1993-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.-a
Opis:
A simple theoretical approach based on Kramers-Krönig relations predicts well the dispersion and birefringence of BaLaGa$\text{}_{3}$O$\text{}_{7}$ and SrLaGa$\text{}_{3}$O$\text{}_{7}$. In the whole transparency region the birefringence of both compounds is too low to offset dispersion in the process of a second harmonic generation, thus the crystals cannot be made phase matchable. Birefringence of BaLaGa$\text{}_{3}$O$\text{}_{7}$ and SrLaGa$\text{}_{3}$O$\text{}_{7}$ is stable with respect to the temperature region of 300-550 K. The refractive indices increase linearly at a rate of 2 × 10$\text{}^{-5}$ K$\text{}^{-1}$ with increasing temperature.
Źródło:
Acta Physica Polonica A; 1993, 83, 2; 167-172
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relaxation of the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ Level of Er$\text{}^{3+}$ in Cs$\text{}_{2}$NaErCl$\text{}_{6}$
Autorzy:
Dominiak-Dzik, G.
Gołąb, S.
Ryba-Romanowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1929800.pdf
Data publikacji:
1993-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
Opis:
Octahedral (O$\text{}_{h}$) symmetry of the RE$\text{}^{3+}$ sites in the Cs$\text{}_{2}$NaRECl$\text{}_{6}$ crystals removes all of the electric dipole intensity from the 4f-4f transitions. Thus the decay of luminescence originating in the excited states of RE ions is governed by phonon assisted (vibronic) transitions, multiphonon relaxation and phonon assisted energy transfer (cross relaxation and energy migration to impurities). Contribution of these processes to the decay of the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ state of erbium in Cs$\text{}_{2}$NaErCl$\text{}_{6}$ has been studied in the 4.2-300 K temperature region. It has been concluded that at low temperatures the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ state decays exclusively by vibronic transitions. At about 100 K the cross relaxation via the $\text{}^{4}$I$\text{}_{9}\text{}_{/}\text{}_{2}$ state becomes operative. Efficiency of this process grows strongly with increasing temperature, reducing the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ lifetime by almost three orders of magnitude. No evidence has been found that multiphonon relaxations contribute to the decay of the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ state.
Źródło:
Acta Physica Polonica A; 1993, 84, 5; 941-944
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence and Lifetimes of Pr$\text{}^{3+}$ Excited States in KLa$\text{}_{1-x}$Pr$\text{}_{x}$(MoO$\text{}_{4}$)$\text{}_{2}$ and KLa$\text{}_{1-x}$Pr$\text{}_{x}$(WO$\text{}_{4}$)$\text{}_{2}$ Crystals
Autorzy:
Macalik, L.
Ryba-Romanowski, W.
Gołąb, S.
Hanuza, J.
Legendziewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1945617.pdf
Data publikacji:
1996-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
78.20.Wc
Opis:
Single crystals of double molybdates and tungstates of the formula KLa$\text{}_{1-x}$Pr$\text{}_{x}$(MO$\text{}_{4}$)$\text{}_{2}$ (M = Mo, W) with a concentration of Pr$\text{}^{3+}$ ions ranging from x=0.1 to x=0.005 have been prepared. Their electronic absorption and emission spectra have been measured and discussed as well as related to their crystal structures. Both the multiphonon relaxation and cross relaxation contribute to the decay of the $\text{}^{3}$P$\text{}_{0}$ level of Pr$\text{}^{3+}$ in these two matrices.
Źródło:
Acta Physica Polonica A; 1996, 90, 2; 301-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Study of SrLaGaO$\text{}_{4}$ and SrLaGa$\text{}_{3}$O$\text{}_{7}$ Doped with Nd$\text{}^{3+}$ and Yb$\text{}^{3+}$
Autorzy:
Ryba-Romanowski, W.
Gołąb, S.
Pisarski, W.
Dominiak-Dzik, G.
Gloubokov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1945654.pdf
Data publikacji:
1996-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
42.70.Hj
Opis:
Single crystals of SrLaGaO$\text{}_{4}$ and SrLaGa$\text{}_{3}$O$\text{}_{7}$ singly doped with Nd and codoped with Nd and Yb have been grown by the Czochralski method. Both the compounds form tetragonal crystals but belong to different space groups. A common feature of these matrices is a structural disorder resulting from statistical distribution of Sr$\text{}^{2+}$ and La$\text{}^{3+}$ ions over the lattice sites. A previous investigation of a laser diode pumped SrLaGa$\text{}_{3}$O$\text{}_{7}$:Nd laser revealed that inhomogeneous broadening of spectral lines of Nd$\text{}^{3+}$ was advantageous for optical pumping and did not influence adversely the extraction efficiency. The present paper deals mainly with optical properties of Yb$\text{}^{3+}$ ions which are of interest for the design of lasers pumped by a diode laser and operating near 1 μm.
Źródło:
Acta Physica Polonica A; 1996, 90, 2; 399-405
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czochralski Growth and Optical Properties οf $(Lu_{x}Gd_{1-x})_2SiO_5$ Solid Solution Crystals Single Doped with $Sm^{3+}$ and $~Dy^{3+}$
Autorzy:
Ryba-Romanowski, W.
Strzęp, A.
Głowacki, M.
Lisiecki, R.
Solarz, P.
Domagala, J.
Powiązania:
https://bibliotekanauki.pl/articles/1399472.pdf
Data publikacji:
2013-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Rz
42.70.Hj
78.40.-q
78.55.Fv
Opis:
Solid solution crystals $(Lu_{x}Gd_{1-x})_2SiO_5$ single doped with $Sm^{3+}$ and $Dy^{3+}$ were grown by the Czochralski method. Segregation coefficients Lu/Gd, melting temperatures and structures of solid solution crystals were determined for 0.15 ≤ x ≤ 0.8. It was found that for x ≥ 0.17 the crystals belong to the monoclinic system within a space group C2/c and their melting temperature diminishes monotonously from 1990C to 1780C when x decreases from 0.8 to 0.15. Disparity of ionic radii of $Lu^{3+}$ and $Gd^{3+}$ induces structural disorder that brings about an inhomogeneous broadening of spectral lines in absorption and emission spectra of incorporated luminescent $Sm^{3+}$ and $Dy^{3+}$ ions. Optical properties of obtained crystals were determined based on results of measurement of absorption and emission spectra and luminescence decay curves. Spectroscopic investigation revealed that $Sm^{3+}$ doped crystals show intense emission distributed in the visible-near infrared region with the most intense band centred at 605 nm and characterized by a branching ratio of 0.43. Emission spectrum of $Dy^{3+}$ doped crystals is dominated by a band centred at 575 nm and characterized by a branching ratio of 0.58. It has been concluded that the systems under study are potential laser materials able to generate visible emission upon GaN/InGaN laser diode pumping.
Źródło:
Acta Physica Polonica A; 2013, 124, 2; 321-328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of As Grown and Induced Structural Defects in SrLaXO$\text{}_{4}$ (x = Al, Ga) Crystals
Autorzy:
Ryba-Romanowski, W.
Gołąb, S.
Dereń, P.
Dominiak-Dzik, G.
Pisarski, W.
Gloubokov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1964366.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
42.70.Hj
Opis:
SrLaGaO$\text{}_{4}$ and SrLaAlO$\text{}_{4}$ substrates grown by the Czochralski method have no twins or subgrains however they show strong tendency to form point defects. The nature of these defects is not well understood yet. They may be associated with deviations from stoichiometry andor oxygen atoms located in the interstitial positions. Virtually all title crystals grown by the Czochralski method display various colours from light green to deeply red owing to light absorption by point defects. Absorption centres appear to be very stable in time and resistant to usual thermal treatment. UV excitation increases the density of defects and gives rise to strong photoluminescence, otherwise too weak to be observed.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 191-196
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Spectroscopy of the $Nd^{3+}$ Luminescence Centres in the $Sr_{4}B_{14}O_{25}:Nd$ Crystal
Autorzy:
Padlyak, B.
Ryba-Romanowski, W.
Lisiecki, R.
Oseledchik, Yu.
Prosvirnin, A.
Kudryavtcev, D.
Svitanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1550132.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.-a
78.40.Ha
78.55.Hx
78.20.Bh
Opis:
Optical absorption, emission and luminescence kinetics of $Nd^{3+}$ centres in the new borate crystal with $Sr_{4}B_{14}O_{25}:Nd$ (Nd content 0.2 wt.%) composition are investigated and analysed. The oscillator strengths ($P_\text{theor}$ and $P_\text{exp}$) for observed absorption transitions and phenomenological intensity parameters $Ω_t$ ($Ω_2$=1.59×$10^{-20} cm^{-1}$, $Ω_{4}$ = 2.06 × $10^{-20} cm^{-1}$, and $Ω_{6}$ = 2.28 × $10^{-20} cm^{-1}$ were calculated based on the standard Judd-Ofelt theory. Using $Ω_t$ parameters the radiative transitions rates $(W_{r})$, branching ratios (β) and radiative lifetime $(τ_{rad})$ for $Nd^{3+}$ centres in the $Sr_{4}B_{14}O_{25}:Nd$ crystal were calculated and analysed. Measured lifetime ($τ_{exp}$ = 105 and 93 μs at T = 10 and 300 K, respectively) is compared with this calculated ($τ_{rad}$ = 331 μs) and quantum efficiency for $Nd^{3+}$ centres from $\text{}^{4}F_{3//2}$ emitting level in the $Sr_{4}B_{14}O_{25}:Nd$ crystal is estimated (η ≅ 30%). Incorporation peculiarities and local structure of $Nd^{3+}$ luminescence centres in the $Sr_{4}B_{14}O_{25}$ crystal and corresponding glass with $4SrO-7B_{2}O_{3}$ composition are discussed on the basis of referenced X-ray diffraction data and presented results.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 104-110
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Resonance and Dielectric Studies of a Nonlinear La$\text{}_{3}$Ga$\text{}_{5.5}$Ta$\text{}_{0.5}$O$\text{}_{14}$ Single Crystal Doped with Erbium
Autorzy:
Bodziony, T.
Typek, J.
Orlowski, M.
Majszczyk, J.
Wabia, M.
Berkowski, M.
Ryba-Romanowski, W.
Guskos, N.
Likodimos, V.
Anagnostakis, E. A.
Powiązania:
https://bibliotekanauki.pl/articles/2035732.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Kg
77.22.Ch
Opis:
Single crystal of erbium doped La$\text{}_{3}$Ga$\text{}_{5.5}$Ta$\text{}_{0.5}$O$\text{}_{14}$ grown by the Czochralski method have been investigated by electron paramagnetic resonance and dielectric spectroscopy methods. Dielectric permittivity ε measurements performed in 90-440 K temperature range have shown negligible dispersion for 1 kHz - 1 MHz frequencies and a Curie-Weiss type behaviour with C=47700 K andθ=-340 K. Electron paramagnetic resonance studies have revealed the presence of two different paramagnetic, monoclinic centres. The calculated g factor values are: g$\text{}_{1}$=1.449, g$\text{}_{2}$=11. 534, g$\text{}_{3}$=4.24 for the main M$\text{}_{1}$ centre and g$\text{}_{1}$=1.98, g$\text{}_{2}$=4.169, g$\text{}_{3}$=4.25 for the weaker M$\text{}_{2}$ centre. The temperature dependence of EPR line intensity for centre M$\text{}_{1}$ and M$\text{}_{2}$ is quite different - while lines attributed to M$\text{}_{1}$ could only be observed at low temperatures, below 20 K, lines of M$\text{}_{2}$ centre persisted up to 200 K. The M$\text{}_{1}$ centre is connected with Er$\text{}^{3+}$ ion entering substitutionally into La$\text{}^{3+}$ site, while M$\text{}_{2}$ is probably connected with 3d ions at the same site, unintentionally introduced into the material as an admixture.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 315-322
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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