Hybrid organic
–inorganic materials for
novel photonic applications
Partha P. Banerjee,
1,* Dean R. Evans,
2Wei Lee,
3Victor Yu. Reshetnyak,
4and Nelson Tansu
51Department of Electrical and Computer Engineering, and Electro-Optics Program,
University of Dayton, Dayton, Ohio 45469, USA
2Air Force Research Laboratory, Materials and Manufacturing Directorate,
Wright-Patterson Air Force Base, Ohio 45433, USA
3
College of Photonics, National Chiao Tung University, Guiren District, Tainan 71150, Taiwan
4
Physics Faculty, National Taras Shevchenko University of Kyiv, Kyiv 01601, Ukraine
5Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics,
Lehigh University, Bethlehem, Pennsylvania 18015, USA *Corresponding author: [email protected]
Received 25 June 2013;
posted 25 June 2013 (Doc. ID 192915); published 31 July 2013
This novel joint feature issue on “Hybrid organic–inorganic materials for photonic applications” in Applied Optics and Optics Materials Express comprises 14 papers on liquid crystals, polymers, photo-conductive materials, and gratings and filters. It is hoped that this feature issue encourages and stim-ulates further research into hybrid materials with enhanced linear and nonlinear optical properties, their mechanisms of operation, and their applications. © 2013 Optical Society of America
OCIS codes: (160.2100) Electro-optical materials; (160.3710) Liquid crystals; (160.5320) Photo-refractive materials; (160.5470) Polymers; (160.1245) Artificially engineered materials; (160.4236) Nanomaterials.
http://dx.doi.org/10.1364/AO.52.000HM1
It is well-known that many natural materials consist of inorganic and organic building blocks where the inorganic part provides mechanical strength and an overall structure to the natural objects, while the organic part delivers bonding between the inor-ganic building blocks and/or the soft tissue. The most obvious advantage of inorganic–organic hybrids is that they can favorably combine the often dissimilar properties of organic and inorganic components in one material. The study of such materials has encouraged many materials researchers to use a bio-mimetic approach to artificially manufacture many
novel materials for use in applications, such as scratch-resistant coatings, dental fillings, fire-retardants, super-capacitors and energy production and storage devices, etc. Electro-optical applications of hybrids include light-emitting diodes, photodiodes, solar cells, sensors (including plasmonic and bio-sensors), field-effect transistors, and efficient nonlin-ear optical devices. Other novel optical applications include organic–inorganic-based meta and plas-monic materials for imaging and sensing.
Hybridization of organic and inorganic materials also opens up yet another new and exciting area in ap-plied optics. The various forms of hybrids in this spe-cial issue have organic and inorganic components, where the inorganics modify the optical and electric properties of the organics. In addition, the organic
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matrix may provide a flexible structure as well as order/structure to the nanomaterials [i.e., nanopar-ticles, liquid crystals (LCs), etc.]. The optical and elec-tric properties of LCs have been shown to be enhanced using nanoparticles. Furthermore, it has also been reported that LCs can be strongly influenced by polymer materials in terms of structuring, ordering, and stabilizing. Outside their role in LC devices, polymers themselves can be hybridized with nanoma-terials, modifying the refractive index, birefringence, and source of charge donors/acceptors. Devices explor-ing these phenomena may find applications in optical beam coupling, optical switches, spatial and temporal filters, tunable photonic crystals, beam shaping, opti-cal displays, and hybridized light valve technologies. Specifically, this feature issue consists of 14 papers comprising four sections: liquid crystals (Lorenz et al. [1], Rudzki et al. [2], Garbovskiy and Glushchenko [3], Lavrič et al. [4], and Yaroshchuk et al. [5]); poly-mers (Nabil et al. [6], Minasyan and Galstian [7], Uklein et al. [8], Nazarova et al. [9] and Sassa et al. [10]); photoconductive materials (Bortolozzo et al. [11] and Mercado-Zúñiga et al. [12]); and gratings and filters (Sheremet et al. [13] and Danaeifar et al. [14]). The papers by Uklein et al. and Sassa et al. ap-pear in Optical Materials Express, while the rest appear in Applied Optics.
In the first section, Lorenz et al. investigated the in-fluence of ferroelectric nanoparticles on the realign-ment of the LC director upon the application of an electric field. In this invited paper, LC nano-dispersion with BaTiO3 ferroelectric nanoparticles showed a more pronounced reorientation with a reduced thresh-old voltage compared to the undoped LC. Rudzki et al. studied the influence of various-size harvested barium titanate nanoparticles on the properties of ferroelec-tric liquid crystal (FLC) using electro-optical and dielectric methods. There is a reduction of the switch-ing time with decrease of BaTiO3 particle size and the (Goldstone mode) viscosity. Garbovskiy and Glushchenko explore how optical and BaTiO3 and PbTiO3ferroelectric properties of stressed ferroelec-tric nanoparticles set a limit on the performance of op-tical and electro-opop-tical devices. Lavrič et al. present a theoretical model accounting for the impact of aniso-tropic MoS2nanoparticles on the blue phase stability region in chiral LC, and validate the model by high-resolution calorimetric and optical measurements. This study revealed that the geometry of the nanopla-telets played an important role in the stabilization of different blue phase structures. Yaroshchuk et al. in-vestigated photoresponsive electro-optical composites comprising cholesteric LC doped with carbon nano-tubes, demonstrating a dual-mode operation with the optical switching between reversible and memory mode. They showed that LC composites with homeo-tropic anchoring exhibit a transition from fingerprint texture to homeotropic nematic texture in the course of a photoinduced unwinding of the cholesteric helix.
Nabil et al. applied polymer dispersed liquid crys-tal (PDLC) as cladding material in a polymer-based
variable optical attenuator. The PDLC-based wave-guide was electro-optically modified at low operating voltages without the need of alignment layer as in the case of LC. Minasyan and Galstian created surface polymer stabilized structures using dual fre-quency controlled LC with thin reactive mesogen films. These devices greatly improved contrast and polarization independence of light scattering, and achieved very short transition times when switching from low to high frequency. Uklein et al. reported on photoinduced modifications of the refractive index of nanoparticulate TiO2-pHEMA organic–inorganic hy-brids. Their results suggested that refraction index variations of the order of 0.005 are attainable, mak-ing these materials candidates for applications in optoelectronics. Nazarova et al. synthesized an aniso-tropic organic/inorganic nanocomposite material us-ing SiO2 nanoparticles in a side-chain azopolymer. They observed about 20% enhancement of the photo-induced birefringence in these composite materials compared to nondoped samples. Sassa et al. studied the influence of a transient dark current on the buildup dynamics of photorefractive polymer index gratings. They concluded that transient dark current flow is an important factor to be considered to optimize conditions for pulsed voltage-assisted PR effects.
Bortolozzo et al. developed a LC light-valve (LCLV) and a self-defocusing medium for near-infrared ap-plications using GaAs:Cr photoconductive sub-strates. The LCLV displays an efficient behavior as an optically addressable transmissive spatial light modulator, with potential future applications in in-terferometric systems or in thermal sensors due to the large Kerr-like nonlinear coefficient. Mercado-Zúñiga et al. developed a photoconductive logic gate based on platinum decorated carbon nanotubes, and characterized the electrical and nonlinear opti-cal properties of these materials. The photoconduc-tive logic gate function OR was experimentally demonstrated.
In the last section of this joint special issue, the in-vited paper by Sheremet et al. showed the results of recording polarization gratings in a combined LC cell made of a substrate covered with a photosensitive chalcogenide orientation layer and a reference sub-strate covered with a rubbed polyimide film. They showed that the application of an ac-field caused a strong increase of the first order diffraction effi-ciency. Danaeifar et al. demonstrated that a 2D sheet of graphene can be used as a simple band-pass filter in terahertz and infrared frequencies. The effects of various material and device parameters on surface plasmon polariton waves and filter specifications were numerically depicted. This material can operate in a wide frequency range, with potential uses as telecommunication transducers and infrared cameras.
In light of the rapid progress in this area, it is hoped that this novel joint feature issue in Applied Optics and Optical Materials Express
encourages and stimulates further research into hybrid materials, their mechanisms of operation, and their applications. The editors feel that the fu-ture of optical hybrid materials will continue to bring to fruition new materials with enhanced lin-ear and nonlinlin-ear optical properties, opening new doors to unexplored application and the improve-ment of performance of current technologies. Poten-tial areas to explore, in addition to the numerous areas explored in this Feature Issue, are optical bio-sensors, optical metamaterials, plasmonics, and interactions at the boundaries of the organic and inorganic components of hybridized materials.
Feature editors
Partha P. Banerjee, University of Dayton, USA Dean R. Evans, Air Force Research Laboratory, USA Wei Lee, National Chiao Tung University, Taiwan Victor Yu. Reshetnyak, National Taras Shevchenko
University of Kyiv, Ukraine
Nelson Tansu, Lehigh University, USA
References
1. A. Lorenz, N. Zimmermann, S. Kumar, D. R. Evans, G. Cook, M. Fernández Martínez, and H.-S. Kitzerow,“X-ray scattering of nematic liquid crystal nanodispersion with negative dielec-tric anisotropy [Invited],” Appl. Opt. 52, E1–E5 (2013). 2. A. Rudzki, D. R. Evans, G. Cook, and W. Haase,“Size
depend-ence of harvested BaTiO3nanoparticles on the electro-optic
and dielectric properties of ferroelectric liquid crystal nanocol-loids,” Appl. Opt. 52, E6–E14 (2013).
3. Y. Garbovskiy and A. Glushchenko, “Optical/ferroelectric characterization of BaTiO3and PbTiO3colloidal nanoparticles
and their applications in hybrid materials technologies,” Appl. Opt.52, E34–E39 (2013).
4. M. Lavrič, G. Cordoyiannis, S. Kralj, V. Tzitzios, G. Nounesis, and Z. Kutnjak,“Effect of anisotropic MoS2nanoparticles on
the blue phase range of a chiral liquid crystal,” Appl. Opt. 52, E47–E52 (2013).
5. O. Yaroshchuk, S. Tomylko, I. Gvozdovskyy, and R. Yamaguchi, “Cholesteric liquid crystal–carbon nanotube composites with photo-settable reversible and memory electro-optic modes,” Appl. Opt. 52, E53–E59 (2013). 6. G. Nabil, W. F. Ho, and H. P. Chan,“Experimental study on the
performance of a variable optical attenuator using polymer dispersed liquid crystal,” Appl. Opt. 52, E15–E21 (2013). 7. A. Minasyan and T. Galstian, “Surface-polymer stabilized
liquid crystals with dual-frequency control,” Appl. Opt. 52, E60–E67 (2013).
8. A. Uklein, P. Gorbovyi, M. Traore, L. Museur, and A. Kanaev, “Photo-induced refraction of nanoparticulate organic-inorganic TiO2-pHEMA hybrids,” Opt. Mater. Express 3,
533–545 (2013).
9. D. Nazarova, L. Nedelchev, P. Sharlandjiev, and V. Dragostinova, “Anisotropic hybrid organic/inorganic (azopolymer/SiO2NP) materials with enhanced photoinduced
birefringence,” Appl. Opt. 52, E28–E33 (2013).
10. T. Sassa, T. Fujihara, J.-I. Mamiya, and M. Kawamoto, “Effects of transient dark currents on the buildup dynamics of refractive index changes in photorefractive polymers excited by pulsed voltage,” Opt. Mater. Express 3, 472–479 (2013).
11. U. Bortolozzo, S. Residori, and J.-P. Huignard,“Transmissive liquid crystal light-valve for near-infrared applications,” Appl. Opt.52, E73–E77 (2013).
12. C. Mercado-Zúñiga, J. R. Vargas-García, F. Cervantes-Sodi, M. Trejo-Valdez, R. Torres-Martínez, and C. Torres-Torres, “Photoconductive logic gate based on platinum decorated carbon nanotubes,” Appl. Opt. 52, E22–E27 (2013).
13. N. Sheremet, Y. Kurioz, K. Slyusarenko, M. Trunov, and Y. Reznikov,“Recording of polarization holograms in a liquid crystal cell with a photosensitive chalcogenide orientation layer [Invited],” Appl. Opt. 52, E40–E46 (2013).
14. M. Danaeifar, N. Granpayeh, A. Mohammadi, and A. Setayesh,“Graphene-based tunable terahertz and infrared band-pass filter,” Appl. Opt. 52, E68–E72 (2013).
