Andrzej Miniewicz
Wrocław University of Technology
OpticsPhysicsLiquid crystalChemistryLaser
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Publications 211
The spectral tuning range of dye lasers is closely associated with the gain profile provided by the utilized luminescent compound. Here, we present the results of studies aimed at broadening the wavelength tuning range in distributed feedback (DFB) lasers, made up of polymeric layers doped with a mixture of two complementary dyes. We have used the 3-(2,2-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) luminescent dye, showing stimulated emission in its crystalline form, and the Rhodamine...
2 CitationsSource
#1Jaroslaw MysliwiecH-Index: 18
#2Konrad CyprychH-Index: 9
Last. Andrzej MiniewiczH-Index: 20
view all 4 authors...
12 CitationsSource
#1Adam SzukalskiH-Index: 11
#2Andrzej MiniewiczH-Index: 20
Last. Jaroslaw MysliwiecH-Index: 18
view all 7 authors...
#1Magdalena Owczarek (UWr: University of Wrocław)H-Index: 8
#2Andrzej MiniewiczH-Index: 20
Last. Ryszard Jakubas (UWr: University of Wrocław)H-Index: 32
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Abstract The performed analysis of crystal structures deposited in Cambridge Structural Database shows that simple salts of amines with N-attached six-membered aliphatic ring favor an acentric arrangement of molecules in a solid state and, therefore, might be suitable candidates for applications that require piezoelectric, ferroelectric, or second-order nonlinear optical properties. Herein we report that hydrochloride and hydrobromide of 4-aminomorpholine indeed crystallize in polar ( Pca 2 1 ) ...
3 CitationsSource
Discovery of E/Z or trans–cis photoisomerization in the azobenzenes and their derivatives had tremendous impact on the whole domain of photochromic materials including photochromic polymers and liquid crystals. Here we show similar configurational photoinduced transformation in a simple derivative of pyrazoline. The X-ray crystallographic investigations of (E)-3-(4-nitrostyryl)-1-phenyl-4,5-dihydro-1H-pyrazole (abbreviated as PY-pNO2) in grown crystals show two different structures comprising of...
13 CitationsSource
#1K. Dradrach (Wrocław University of Technology)H-Index: 3
#2Stanislaw Bartkiewicz (Wrocław University of Technology)H-Index: 20
Last. Andrzej Miniewicz (Wrocław University of Technology)H-Index: 20
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Using the direct coupling mechanism of light with a liquid via molecular absorption, i.e. the opto-thermal effect, we demonstrate the formation of well-controlled three-dimensional circular flows, i.e. a toroidal vortex, inside the liquid crystal (LC) droplet placed on a glass plate in its isotropic phase. We investigated the behavior of a droplet formed of a phototropic liquid crystal and composed of a mesogenic azobenzene derivative under the Gaussian beam light illumination in four different ...
7 CitationsSource
#1W. TuralskiH-Index: 2
Last. Andrzej MiniewiczH-Index: 20
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#1O. Morawski (PAN: Polish Academy of Sciences)H-Index: 6
#2Bolesław Kozankiewicz (PAN: Polish Academy of Sciences)H-Index: 14
Last. Andrzej L. Sobolewski (PAN: Polish Academy of Sciences)H-Index: 43
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A pyrazoline derivative, 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP), is studied by using optical spectroscopy methods in several solvents at room and at low temperatures. The DCNP molecule reveals a complex photophysics behavior, which is sensitive to solvent polarity, proticity, temperature and viscosity and arises from the presence of two rotational degrees of freedom of the dicyanovinyl group--the torsion around the double C=C bond and the s-trans-s-cis isomerization aroun...
5 CitationsSource
#1Lech Sznitko (Wrocław University of Technology)H-Index: 15
#2Jaroslaw Mysliwiec (Wrocław University of Technology)H-Index: 18
Last. Andrzej Miniewicz (Wrocław University of Technology)H-Index: 20
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In this review article, we describe the basic principles of random laser operation with particular emphasis on π-conjugated, dye-doped and biologically inspired polymers. Random lasers are unusual types of lasers that use disorder in the light amplifying medium to provide positive feedback for laser operation. Organic systems like polymers are affected with disorder resulting both from their molecular structure and fabrication techniques. Due to this fact polymers seem to fit to role of random l...
23 CitationsSource
#1Andrzej Miniewicz (Wrocław University of Technology)H-Index: 20
#2M. Tomkowicz (Wrocław University of Technology)H-Index: 1
Last. Michał Dutkiewicz (Adam Mickiewicz University in Poznań)H-Index: 15
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Abstract Hybrid inorganic–organic nanoparticles based on cubic siloxane cage (RSiO3/2)8, known as polyhedral oligosilsesquioxane (POSS), have been functionalized by eight groups of azo-benzene mesogens and dispersed in poly(methyl methacrylate) PMMA matrix. Presence of azo-benzene units adds an important light-driven functionality to the system due to their photoisomerization resulting in refractive index and/or absorption changes of the whole system. The polymer films containing various concent...
6 CitationsSource