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1

Relaxation of the ^{4}S_{3/2} Level of Er^{3+} in Cs_{2}NaErCl_{6}

100%

Dominiak-Dzik G., Gołąb S., Ryba-Romanowski W.

Acta Physica Polonica A

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1993

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vol. 84

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issue 5

941-944

EN

Octahedral (O_{h}) symmetry of the RE^{3+} sites in the Cs_{2}NaRECl_{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 ^{4}S_{3/2} state of erbium in Cs_{2}NaErCl_{6} has been studied in the 4.2-300 K temperature region. It has been concluded that at low temperatures the ^{4}S_{3/2} state decays exclusively by vibronic transitions. At about 100 K the cross relaxation via the ^{4}I_{9/2} state becomes operative. Efficiency of this process grows strongly with increasing temperature, reducing the ^{4}S_{3/2} lifetime by almost three orders of magnitude. No evidence has been found that multiphonon relaxations contribute to the decay of the ^{4}S_{3/2} state.

2

Optical Study of SrLaGaO_{4} and SrLaGa_{3}O_{7} Doped with Nd^{3+} and Yb^{3+}

88%

Ryba-Romanowski W., Gołąb S., Pisarski W., Dominiak-Dzik G., Gloubokov A.

Acta Physica Polonica A

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1996

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vol. 90

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issue 2

399-406

EN

Single crystals of SrLaGaO_{4} and SrLaGa_{3}O_{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^{2+} and La^{3+} ions over the lattice sites. A previous investigation of a laser diode pumped SrLaGa_{3}O_{7}:Nd laser revealed that inhomogeneous broadening of spectral lines of Nd^{3+} was advantageous for optical pumping and did not influence adversely the extraction efficiency. The present paper deals mainly with optical properties of Yb^{3+} ions which are of interest for the design of lasers pumped by a diode laser and operating near 1 μm.

3

Investigation of As Grown and Induced Structural Defects in SrLaXO_{4} (x = Al, Ga) Crystals

76%

Ryba-Romanowski W., Gołąb S., Dereń P., Dominiak-Dzik G., Pisarski W., Gloubokov A.

Acta Physica Polonica A

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1997

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vol. 92

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issue 1

191-196

EN

SrLaGaO_{4} and SrLaAlO_{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.

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3 Acta Physica Polonica A

1 1997

1 1996

1 1993

3 Dominiak-Dzik G.

3 Gołąb S.

3 Ryba-Romanowski W.

2 Gloubokov A.

2 Pisarski W.

1 Dereń P.

Relaxation of the ^{4}S_{3/2} Level of Er^{3+} in Cs_{2}NaErCl_{6}

Optical Study of SrLaGaO_{4} and SrLaGa_{3}O_{7} Doped with Nd^{3+} and Yb^{3+}

Investigation of As Grown and Induced Structural Defects in SrLaXO_{4} (x = Al, Ga) Crystals