@article{ZieglerFischerMenzeletal.1998,
  author    = {Ziegler, A. and Fischer, Thomas M. and Menzel, Henning and Stumpe, Joachim},
  title     = {Photo-Induced modification and photo-orientation in LB-multilayers of thermotropic polymers containing azobenzene side groups},
  year      = {1998},
  language  = {en}
}
@article{VixSapichStumpeetal.1998,
  author    = {Vix, A. and Sapich, B. and Stumpe, Joachim and Stocker, W. and Rabe, J. P.},
  title     = {Interfacial ordering and photo-orientation of a liquid crystalline main polymer},
  year      = {1998},
  language  = {en}
}
@article{TomczykSobolewskaNagyetal.2013,
  author    = {Tomczyk, Jaroslaw and Sobolewska, Anna and Nagy, Zsuzsanna T. and Guillon, Daniel and Donnio, Bertrand and Stumpe, Joachim},
  title     = {Photo- and thermal-processing of azobenzene-containing star-shaped liquid crystals},
  series = {Journal of materials chemistry : C, Materials for optical and electronic devices},
  volume    = {1},
  journal   = {Journal of materials chemistry : C, Materials for optical and electronic devices},
  number    = {5},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2050-7526},
  doi       = {10.1039/c2tc00627h},
  pages     = {924 -- 932},
  year      = {2013},
  abstract  = {A new class of star-shaped, liquid crystalline, low-molecular weight compounds functionalized with photochromic azobenzene and mesogenic groups was investigated in terms of light-induced anisotropy. The behaviour of the materials under the action of light with simultaneous or subsequent thermal treatment was examined with respect to the induction of anisotropy. The unconventional UV light treatment prior to the irradiation with linearly polarized light allowed induction of very high values of anisotropy (D = 0.77) at room temperature. Moreover, the simultaneous action of light and temperature led to the induction of higher values of dichroism in comparison with anisotropy generated by the standard procedure. Subsequent thermal treatment led to dewetting and the formation of 3D macroscopic stripe- and dome-like structures for one of the investigated compounds. Despite photoinduction of anisotropy by a single beam, the formation of polarization and surface relief gratings by two-beam interference pattern was also investigated.},
  language  = {en}
}
@article{TejedorOriolPinoletal.2005,
  author    = {Tejedor, R. M. and Oriol, L. and Pinol, M. and Serrano, J. L. and Strehmel, Veronika and Stiller, Burkhard and Stumpe, Joachim},
  title     = {Photoreactive main-chain liquid-crystalline polyesters : Synthesis, characterization, and photochemistry},
  issn      = {0887-624X},
  year      = {2005},
  abstract  = {Three series of semiflexible and rigid main-chain polyesters containing photoreactive mesogenic units derived from p-phenylenediacrylic acid (PDA) and cinnamic acid have been synthesized by high-temperature polycondensation. The thermal and mesomorphic properties of the polymers have been determined. The photochemical behavior of polymer P-[1]-T, which contains a PDA unit, has been studied both in solution and in films. In solution, [2+2] photocycloaddition, E/Z photoisomerization, and photo-Fries rearrangement can take place. In contrast, the dominant process in spin-coated films is the [2+2] photocycloaddition reaction, which causes crosslinking of the polymer. In films, the photochemistry and induction of anisotropy are strongly influenced by the aggregation of the PDA phenylester unit. A dichroism of about 0.2 has been induced in films by irradiation with linearly polarized UV light, and thus the capability of these films to induce optical anisotropy and align liquid crystals has been demonstrated. Liquid-crystalline cells have been made with polarized irradiated films of P[1]-T as aligning layers. A commercial liquid-crystalline mixture has been used for this study, and a similar liquid-crystalline order determined by polarized Fourier transform infrared to a commercial cell with rubbed polyimide as an aligning layer has been detected. Because of crosslinking of the irradiated P[1]-T photoaligning layer, the photoinduced anisotropy is stable at high temperatures, and the liquid-crystalline molecules are insoluble in the irradiated polymer. (c) 2005 Wiley Periodicals, Inc},
  language  = {en}
}
@article{StumpeSakhnoGritsaietal.2014,
  author    = {Stumpe, Joachim and Sakhno, O. and Gritsai, Y. and Rosenhauer, R. and Fischer, Th. and Rutloh, Michael and Schaal, F. and Weidenfeld, S. and Jetter, M. and Michler, P. and Pruss, C. and Osten, W.},
  title     = {Active and passive LC based polarization elements},
  series = {Molecular crystals and liquid crystals},
  volume    = {594},
  journal   = {Molecular crystals and liquid crystals},
  number    = {1},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {1542-1406},
  doi       = {10.1080/15421406.2014.917503},
  pages     = {140 -- 149},
  year      = {2014},
  abstract  = {Passive and active polarization elements were created by surface and bulk photo-alignment of LCs, reactive LCs, photo-sensitive LCP and photo-curable monomer/LC composites. The use of different photo-sensitive liquid crystalline materials for the development of highly anisotropic elements with high spatial resolution and stability or, alternatively, fast switch ability will be discussed. Photo-active and voltage tunable polarization and diffraction elements are presented. For active micro-optic application a photo-addressed patterned retarder was created. Electrically switchable diffraction gratings were generated by interference exposure of photo-curable LC composites at room temperature characterized by droplet free morphology. These polarization sensitive diffraction elements are characterized be excellent optical properties and low switching times.},
  language  = {en}
}
@article{StumpeGeueFischeretal.1995,
  author    = {Stumpe, Joachim and Geue, Thomas and Fischer, Thomas M. and Menzel, Henning},
  title     = {Photochemically induced changes of structures in LB-multilayers of amphotropic polymers},
  year      = {1995},
  language  = {en}
}
@article{StumpeFischerRutlohetal.1998,
  author    = {Stumpe, Joachim and Fischer, Thomas M. and Rutloh, M. and Meier, Johann Georg},
  title     = {Photo-Induced orientation effects parallel and perpendicular to the polarization vector of the incident light observed in the same Azobenzene containing LC polymer.},
  year      = {1998},
  language  = {en}
}
@article{SchabBalcerzakFlakusJarczykJedrykaetal.2015,
  author    = {Schab-Balcerzak, Ewa and Flakus, Henryk and Jarczyk-Jedryka, Anna and Konieczkowska, Jolanta and Siwy, Mariola and Bijak, Katarzyna and Sobolewska, Anna and Stumpe, Joachim},
  title     = {Photochromic supramolecular azopolyimides based on hydrogen bonds},
  series = {Optical materials : an international journal on the physics and chemistry of optical materials and their applications, including devices},
  volume    = {47},
  journal   = {Optical materials : an international journal on the physics and chemistry of optical materials and their applications, including devices},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-3467},
  doi       = {10.1016/j.optmat.2015.06.029},
  pages     = {501 -- 511},
  year      = {2015},
  abstract  = {The approach of deriving new photoresponsive active supramolecular azopolymers based on the hydrogen bonds is described. Polymers with imide rings, i.e., poly(esterimide)s and poly(etherimide)s, with phenolic hydroxyl or carboxylic groups were applied as matrixes for the polymer dye supramolecular systems. Supramolecular films were built on the basis of the hydrogen bonds between the functional groups of the polymers and various azochromophores, that is, 4-phenylazophenol, 4-[4-(6-hydroxyhexy loxy)phenylazo]benzene, 4[4-(6-hexadecaneoxy)phenylazo]pyridine and 4-(4-hydroxyphenylazo)-pyridine. The hydrogen bonding interaction in azo-systems were studied by Fourier transform infrared spectroscopy and for selected assembles by H-1 NMR technique. The obtained polyimide azo-assembles were characterized by X-ray diffraction and DSC measurements. H-bonds allow attaching a chromophore to each repeating unit of the polymer, thereby suppressing the macroscopic phase separation except for the systems based on 4-[4-(6-hydroxyhexyloxy)phenylazo]benzene. H-bonds systems were amorphous and revealed glass transition temperatures lower than for the polyimide matrixes (170-260 degrees C). The photoresponsive behavior of the azo-assemblies was tasted in holographic recording experiment. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{SchaalRutlohWeidenfeldetal.2018,
  author    = {Schaal, Frederik and Rutloh, Michael and Weidenfeld, Susanne and Stumpe, Joachim and Michler, Peter and Pruss, Christof and Osten, Wolfgang},
  title     = {Optically addressed modulator for tunable spatial polarization control},
  series = {Optics express : the international electronic journal of optics},
  volume    = {26},
  journal   = {Optics express : the international electronic journal of optics},
  number    = {21},
  publisher = {Optical Society of America},
  address   = {Washington},
  issn      = {1094-4087},
  doi       = {10.1364/OE.26.028119},
  pages     = {28119 -- 28130},
  year      = {2018},
  abstract  = {We present an optically addressed non-pixelated spatial light modulator. The system is based on reversible photoalignment of a LC cell using a red light sensitive novel azobenzene photoalignment layer. It is an electrode-free device that manipulates the liquid crystal orientation and consequently the polarization via light without artifacts caused by electrodes. The capability to miniaturize the spatial light modulator allows the integration into a microscope objective. This includes a miniaturized 200 channel optical addressing system based on a VCSEL array and hybrid refractive-diffractive beam shapers. As an application example, the utilization as a microscope objective integrated analog phase contrast modulator is shown. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement},
  language  = {en}
}
@misc{SchaalRutlohWeidenfeldetal.2018,
  author    = {Schaal, Frederik and Rutloh, Michael and Weidenfeld, Susanne and Stumpe, Joachim and Michler, Peter and Pruss, Christof and Osten, Wolfgang},
  title     = {Optically addressed modulator for tunable spatial polarization control},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1001},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44626},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446263},
  pages     = {28119 -- 28130},
  year      = {2018},
  abstract  = {We present an optically addressed non-pixelated spatial light modulator. The system is based on reversible photoalignment of a LC cell using a red light sensitive novel azobenzene photoalignment layer. It is an electrode-free device that manipulates the liquid crystal orientation and consequently the polarization via light without artifacts caused by electrodes. The capability to miniaturize the spatial light modulator allows the integration into a microscope objective. This includes a miniaturized 200 channel optical addressing system based on a VCSEL array and hybrid refractive-diffractive beam shapers. As an application example, the utilization as a microscope objective integrated analog phase contrast modulator is shown. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement},
  language  = {en}
}
@article{SapichKrawinkelKricheldorfetal.1998,
  author    = {Sapich, B. and Krawinkel, Th. and Kricheldorf, H. R. and Stumpe, Joachim},
  title     = {New polymer syntheses 95. Photosetting cholesteric polyesters derived from 4-hydroxycinnamic acid and isosorbide.},
  year      = {1998},
  language  = {en}
}
@article{SakhnoGoldenbergStumpeetal.2009,
  author    = {Sakhno, Oksana V. and Goldenberg, Leonid M. and Stumpe, Joachim and Smirnova, Tatiana N.},
  title     = {Effective volume holographic structures based on organic-inorganic photopolymer nanocomposites},
  issn      = {1464-4258},
  doi       = {10.1088/1464-4258/11/2/024013},
  year      = {2009},
  abstract  = {We demonstrate a practical approach for the development of a broad range of nanocomposites based on acrylate polymers and organically capped inorganic nanoparticles (NPs). The submicrometer scale volume patterning of the nanocomposites using holographic photopolymerization was investigated. The specific adjustment of both the material parameters (core-shell of the NP, monomer mixture, concentrations) and the patterning conditions led to materials that were suitable for the fabrication of effective optical diffractive elements and specific functional microdevices with light-emissive and nonlinear optical (NLO) properties. The nanocomposite preparation and properties, their holographic performance and some examples of functional polymer-NP structures are reported.},
  language  = {en}
}
@article{RyabchunSakhnoStumpeetal.2017,
  author    = {Ryabchun, Alexander and Sakhno, Oksana and Stumpe, Joachim and Bobrovsky, Alexey},
  title     = {Full-Polymer Cholesteric Composites for Transmission and Reflection Holographic Gratings},
  series = {Advanced optical materials},
  volume    = {5},
  journal   = {Advanced optical materials},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {2195-1071},
  doi       = {10.1002/adom.201700314},
  pages     = {376 -- 379},
  year      = {2017},
  abstract  = {A new type of self-organized materials based on cholesteric networks filled with photoactive side-chain copolymer is being developed. Supramolecular helical structure of cholesteric polymer network resulting in the selective reflection is used as a photonic scaffold. Photochromic azobenzene-containing nematic copolymer is embedded in cholesteric scaffold and utilized as a photoactive media for optical pattering. 1D and 2D transmission diffraction gratings are successfully recorded in composite films by holographic technique. For the first time the possibility to create selective reflection gratings in cholesteric material mimicking the natural optical properties of cholesteric mesophase is demonstrated. That enables the coexistence of two selective gratings, where one has an intrinsic cholesteric periodic helical structure and the other is a holographic grating generated in photochromic polymer. The full-polymer composites provide high light-induced optical anisotropy due to effective photo-orientation of side-chain fragments of the azobenzene-containing liquid crystalline polymer, and prevent the degradation of the helical superstructure maintaining all optical properties of cholesteric mesophase. The proposed class of optical materials could be easily applied to a broad range of polymeric materials with specific functionality. The versatility of the adjustment and material preprogramming combined with high optical performance makes these materials a highly promising candidate for modern optical and photonic applications.},
  language  = {en}
}
@article{RyabchunRaguzinStumpeetal.2016,
  author    = {Ryabchun, Alexander and Raguzin, Ivan and Stumpe, Joachim and Shibaev, Valery and Bobrovsky, Alexey},
  title     = {Cholesteric Polymer Scaffolds Filled with Azobenzene-Containing Nematic Mixture with Phototunable Optical Properties},
  series = {Scientific reports},
  volume    = {8},
  journal   = {Scientific reports},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1944-8244},
  doi       = {10.1021/acsami.6b09642},
  pages     = {27227 -- 27235},
  year      = {2016},
  abstract  = {The past two decades witnessed tremendous progress in the field of creation of different types of responsive materials. Cholesteric polymer networks present a very promising class of smart materials due to the combination of the unique optical properties of cholesteric mesophase and high mechanical properties of polymer networks. In the present work we demonstrate the possibility of fast and reversible photocontrol of the optical properties of cholesteric polymer networks. Several cholesteric photopolymerizable mixtures are prepared, and porous cholesteric network films with different helix pitches are produced by polymerization of these mixtures. An effective and simple method of the introduction of photochromic azobenzene-containing nematic mixture capable of isothermal photoinducing the nematic isotropic phase transition into the porous polymer matrix is developed, It is found that cross-linking density and degree of polymer network filling with a photochromic nematic mixture strongly influence the photo-optical behavior of the obtained composite films. In particular, the densely cross-linked films are characterized by a decrease in selective light reflection bandwidth, whereas weakly cross-linked systems display two processes: the shift of selective light reflection peak and decrease of its width. It is noteworthy that the obtained cholesteric materials are shown to be very promising for the variety applications in optoelectronics and photonics.},
  language  = {en}
}
@article{RyabchunBobrovskyStumpeetal.2015,
  author    = {Ryabchun, Alexander and Bobrovsky, Alexey and Stumpe, Joachim and Shibaev, Valery},
  title     = {Electroinduced Diffraction Gratings in Cholesteric Polymer with Phototunable Helix Pitch},
  series = {Advanced optical materials},
  volume    = {3},
  journal   = {Advanced optical materials},
  number    = {10},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {2195-1071},
  doi       = {10.1002/adom.201500293},
  pages     = {1462 -- 1469},
  year      = {2015},
  abstract  = {For the first time the cholesteric mixture containing nematic polymer with small amount of chiral-photochromic dopant is used for electroinduced diffraction gratings production. The gratings are obtained by applying electric field to the planar-aligned cholesteric polymer layer causing its periodical distortion. Material developed permits manipulating supramolecular helical structure by means of UV exposure resulting in helix untwisting. Photo-controlling of helix pitch brings to change parameters of the electroinduced gratings. Due to macromolecular "nature" of the material one can easily stabilize electroinduced gratings by fast sample cooling. All-known cholesteric grating types are realized in the studied polymer material. It is observed that the grating vector can be oriented along or perpendicular to the rubbing direction of the cell. It is shown that the diffraction efficiency is dictated by grating type and the amplitude of the applied electric field and can achieve about 80\%. Moreover, the period of gratings can be tuned upon UV light illumination. The possibility of 2D gratings creation is also demonstrated. The described material and approach gives an opportunity to easily fabricate a variety of diffraction gratings with flexibly controllable parameters. Such gratings can be potentially applied in optics, optoelectronics, and photonics as intelligent diffraction elements.},
  language  = {en}
}
@article{RutlohZebgerHoffmannetal.1998,
  author    = {Rutloh, M. and Zebger, I. and Hoffmann, U. and Stumpe, Joachim and Siesler, H. W.},
  title     = {Photo-Induced orientation effects parallel and perpendicular to the polarization vector of the incident light observed in the same azobenzene containing LC polymer},
  year      = {1998},
  language  = {en}
}
@article{PadeSchmidtStumpeetal.1996,
  author    = {Pade, Sylvia and Schmidt, Hartmut and Stumpe, Joachim and Fischer, Thomas M.},
  title     = {(Micro-)fluorescence spectroscopy of side chain polymers with bezanilide moieties},
  year      = {1996},
  language  = {en}
}
@article{NagyHeinrichGuillonetal.2012,
  author    = {Nagy, Zsuzsanna T. and Heinrich, Benoit and Guillon, Daniel and Tomczyk, Jaroslaw and Stumpe, Joachim and Donnio, Bertrand},
  title     = {Heterolithic azobenzene-containing supermolecular tripedal liquid crystals self-organizing into highly segregated bilayered smectic phases},
  series = {Journal of materials chemistry},
  volume    = {22},
  journal   = {Journal of materials chemistry},
  number    = {35},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {0959-9428},
  doi       = {10.1039/c2jm33751g},
  pages     = {18614 -- 18622},
  year      = {2012},
  abstract  = {Synthesis, self-organization, and optical properties of supermolecular tripedal liquid crystals incorporating various prototypical mesogenic units such as alkoxy-azobenzene (AZB), alkoxy-biphenylene (BPH) or alkoxy-cyanobiphenyl (OCB) derivatives are reported. Different molecular systems were designed in order to sequentially incorporate the smectogenic-like alkoxy-azobenzene-based chromophore within the molecular structure, whose relative proportion is selectively varied by exchanging with the other mesogens. A divergent synthetic mode was elaborated for their synthesis, starting from the regioselective functionalization of the phloroglucinol-based (PG) inner core. This methodology allowed the preparation of several sets of unconventional tripedal oligomers with conjugated heterolithic structures (made of different blocks, e.g. PG(6)AZB(x)BPH(3-x) and PG(6)AZB(x)OCB(3-x), x = 1 or 2) along the homolithic parents (all identical blocks, e.g. PG(z)AZB(3), z = 6 or 11, z is the number of methylene in the spacer between PG and the protomesogen, PG(6)BPH(3), and PG(6)OCB(3)), respectively. Essentially all the synthesized systems behave as thermotropic liquid crystals and show various types of highly segregated multilayered smectic phases, or, in one case, a nematic phase, depending on the nature of the constitutive anisotropic blocks and on the molecular topology (homolithic versus heterolithic, mesogenic ratio x : 3 - x). The effects of these structural modifications on the mesomorphism (mesophase structures, temperature ranges, and thermodynamic stability) have been investigated by differential scanning calorimetry and small-angle X-ray diffraction experiments combined with dilatometric measurements. Models describing the various supramolecular organizations of these tripedes into such multilayered structures are proposed and discussed. Preliminary results of the investigations of their optical properties will also be presented.},
  language  = {en}
}
@article{MenzelRuetherStumpeetal.1998,
  author    = {Menzel, Henning and R{\"u}ther, M. and Stumpe, Joachim and Fischer, Thomas M.},
  title     = {Discrimination of structural order and chromophore aggregation as factors effecting the photo-reorientation of Azobenzene in copolyglutamate LB-films.},
  year      = {1998},
  language  = {en}
}
@article{MenzelRuetherStumpeetal.1998,
  author    = {Menzel, Henning and R{\"u}ther, M. and Stumpe, Joachim and Fischer, Thomas M.},
  title     = {Discrimination of structural order and chromophore aggregation as factors effecting the photo-reorientation of azobenzene in co-polyglutamate LB-films},
  year      = {1998},
  language  = {en}
}