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5 Acta Physica Polonica A

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Lateral Waves in Anisotropic Optical Waveguides

100%

Wabia M.

Acta Physica Polonica A

1992

tom 81

nr 4-5

503-516

The paper deals with the properties of lateral waves in uniaxial optical waveguides. The lateral waves are closely associated with the phenomenon of the total reflection and arise due to the presence of branch point singularities of the reflection coefficients. In the structure of uniaxial asymmetric waveguides two sets of the lateral waves may propagate along two interfaces of the waveguide. A detailed wave-optical analysis for the propagation is presented.

Field Excited by Plane Waves in Anisotropic Optical Waveguide

100%

Wabia M.

Acta Physica Polonica A

1992

tom 81

nr 6

639-645

Displacing a linear source exciting the waveguide along an arbitrary fixed direction to infinity one can create the conditions in which the wave-guide is excited by a plane wave. The nature of the excited field in a wave-guide is complicated. On the upper plane of the waveguide x = +l one always deals with the radiation mode whereas on the lower boundary of the waveguide x = -l one can deal with the radiation mode or the surface-type wave.

Stationary Solutions of the Electromagnetic TE Waves Propagating Along a Single Interface Between the Two Kerr-Type Nonlinear Media

63%

Wabia M. , Zaleśny J.

Acta Physica Polonica A

1999

tom 95

nr 5

801-812

Propagation of the TE electromagnetic waves in self-focusing medium is governed by the nonlinear Schrödinger equation. In this paper the stationary solutions of this equation have been systematically presented. The phase-plane method, qualitative analysis, and mechanical interpretation of the differential equations are widely used. It is well known that TE waves can be guided by a single interface between two semi-infinite media, providing that one of the media has a self-focusing (Kerr-type) nonlinearity. This special solution is called a spatial soliton. In this paper our interests are not restricted to the soliton solutions. In the context of the nonlinear substrate and cladding we have found solutions which could be useful to describe also the incident light in a nonlinear medium. This result is the main point of the paper. Some of the presented stationary solutions were already used in a similar optical context in the literature but we show a little wider class of solutions. In the last section we review and illustrate some results concerning the spatial soliton solution.

Charge Transfer and f-f Transitions Studied by Photoacoustic Spectroscopy of [R(NO_3)_2(PicBH)_2]NO_3 and [R(NO_3)_3(PicBH)_2] Complexes (R - Rare Earth Ion)

32%

Guskos N. , Papadopoulos G. , Majszczyk J. , Typek J. , Wabia M. , Likodimos V. , Paschalidis D. , Tossidis I. , Aidinis k.

Acta Physica Polonica A

2003

tom 103

nr 2-3

301-313

High-resolution photoacoustic spectra of trinitrato-bis[N-(2-pyridyl-methylene)-N'-benzoyl-hydrazine]R (III), (R = La, Ce, Pr), and binitrato-bis[N-(2-pyridylmethylene)-N'-benzoyl-hydrazine]R(III) nitrate (R=Y, Nd, Eu, Yb, Tb, Gd, Ho, Dy, Er) complexes, in the visual region, were studied for powder samples. Very intense photoacoustic spectra of various shapes were attributed to the intraligand transitions of the π → π* type located mainly on the C=N group and the n → π* transitions located on the carbonyl group. The intensity of these transitions essentially depends on the type of rare earth ions. The existence of f-f electron transitions could influence the relaxation processes, which play an important role in intensity determination of the above transitions. For many investigated samples the energy levels of excited states of rare earth ions were identified (f-f electron transitions). The radiation energy for some of the rare earth ions were compared with the d-d electron transitions of certain copper(II) organometallic complexes, which are very important in biogenic systems. The correlation between ions with localized and extended wave functions is suggested.

Magnetic Resonance and Dielectric Studies of a Nonlinear La_3Ga_{5.5}Ta_{0.5}O_{14} Single Crystal Doped with Erbium

32%

Bodziony T. , Typek J. , Orlowski M. , Majszczyk J. , Wabia M. , Berkowski M. , Ryba-Romanowski W. , Guskos N. , Likodimos V. , Anagnostakis E.

Acta Physica Polonica A

2003

tom 103

nr 2-3

315-322

Single crystal of erbium doped La_3Ga_{5.5}Ta_{0.5}O_{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_1=1.449, g_2=11. 534, g_3=4.24 for the main M_1 centre and g_1=1.98, g_2=4.169, g_3=4.25 for the weaker M_2 centre. The temperature dependence of EPR line intensity for centre M_1 and M_2 is quite different - while lines attributed to M_1 could only be observed at low temperatures, below 20 K, lines of M_2 centre persisted up to 200 K. The M_1 centre is connected with Er^{3+} ion entering substitutionally into La^{3+} site, while M_2 is probably connected with 3d ions at the same site, unintentionally introduced into the material as an admixture.