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Taghavi I, Dehghannasiri R, Fan T, Tofini A, Moradinejad H, Efterkhar AA, Shekhar S, Chrostowski L, Jaeger NAF, Adibi A. Enhanced poling and infiltration for highly efficient electro-optic polymer-based Mach-Zehnder modulators. OPTICS EXPRESS 2022; 30:27841-27857. [PMID: 36236945 DOI: 10.1364/oe.460830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/20/2022] [Indexed: 06/16/2023]
Abstract
An ultra-narrow 40-nm slotted waveguide is fabricated to enable highly efficient, electro-optic polymer modulators. Our measurement results indicate that VπL's below ∼ 1.19 V.mm are possible for the balanced Mach-Zehnder modulators using this ultra-narrow slotted waveguide on a hybrid silicon-organic hybrid platform. Our simulations suggest that VπL's can be further reduced to ∼ 0.35 V.mm if appropriate doping is utilized. In addition to adapting standard recipes, we developed two novel fabrication processes to achieve miniaturized devices with high modulation sensitivity. To boost compactness and decrease the overall footprint, we use a fabrication approach based on air bridge interconnects on thick, thermally-reflowed, MaN 2410 E-beam resist protected by an alumina layer. To overcome the challenges of high currents and imperfect infiltration of polymers into ultra-narrow slots, we use a carefully designed, atomically-thin layer of TiO2 as a carrier barrier to enhance the efficiency of our electro-optic polymers. The anticipated increase in total capacitance due to the TiO2 layer is negligible. Applying our TiO2 surface treatment to the ultra-narrow slot allows us to obtain an improved index change efficiency (∂n/∂V) of ∼ 22% for a 5 nm TiO2 layer. Furthermore, compared to non-optimized cases, our peak measured current during poling is reduced by a factor of ∼ 3.
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Mao J, Sato H, Bannaron A, Hong J, Lu GW, Yokoyama S. Efficient silicon and side-cladding waveguide modulator with electro-optic polymer. OPTICS EXPRESS 2022; 30:1885-1895. [PMID: 35209341 DOI: 10.1364/oe.447616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Efficient electro-optic (EO) modulation can be generated in the hybrid silicon modulator with EO polymer in the form of an in-plane coplanar waveguide and electrode structure. Strong confinement of the optical field in the hybrid structure is critical to performing efficient electric poling and modulation of the EO polymer. The waveguide consists of silica-based side claddings and an EO core for increasing the integral of the optical field and the overlap interaction between the optical field and the modulated electric field within the EO polymer. We discuss in detail the volume resistivity dependence of the efficiency of electric poling and modulation for various side-cladding materials. In a Mach-Zehnder interferometer modulator, the measured half-wave-voltage length product (VπL) is 1.9 V·cm at an optical communication wavelength of 1,550 nm under the TE optical mode operation. The high-speed signaling of the device is demonstrated by generating on-off-keying transmission at signal rates up to 52 Gbit/s with a Q factor of 6.1 at a drive voltage of 2.0 Vpp.
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Rega R, Gennari O, Mecozzi L, Pagliarulo V, Mugnano M, Oleandro E, Nazzaro F, Ferraro P, Grilli S. Pyro-Electrification of Freestanding Polymer Sheets: A New Tool for Cation-Free Manipulation of Cell Adhesion in vitro. Front Chem 2019; 7:429. [PMID: 31275921 PMCID: PMC6594357 DOI: 10.3389/fchem.2019.00429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/27/2019] [Indexed: 12/15/2022] Open
Abstract
Localized electric fields have become, in recent years, a source of inspiration to researchers and laboratories thanks to a huge amount of applications derived from it, including positioning of microparticles as building blocks for electrical, optical, and magnetic devices. The possibility of producing polymeric materials with surface charge thus opens new perspectives for applications where process simplicity and cost-effectiveness of flexible electronics are of fundamental importance. In particular, the influence of surface charges is widely studied and is a critical issue especially when new materials and functional technologies are introduced. Here, we report a voltage-free pyro-electrification (PE) process able to induce a permanent dipole orientation into polymer sheets under both mono- and bipolar distribution. The technique makes use of the pyroelectric effect for generating electric potentials on the order of kilovolts by an easy-to-accomplish thermal treatment of ferroelectric lithium niobate (LN) crystals. The PE allows us to avoid the expensive and time-consuming fabrication of high-power electrical circuits, as occurs in traditional generator-based techniques. Since the technique is fully compatible with spin-coating-based procedures, the pyro-electrified polymer sheets are easily peeled off the surface of the LN crystal after PE completion, thus providing highly stable and freestanding charged sheets. We show the reliability of the technique for different polymers and for different applications ranging from live cell patterning to biofilm formation tests for bacteria linked to food-processing environments.
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Affiliation(s)
- Romina Rega
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
| | - Oriella Gennari
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
| | - Laura Mecozzi
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
| | - Vito Pagliarulo
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
| | - Martina Mugnano
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
| | - Emilia Oleandro
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
- Department of Mathematics and Physics, University of Campania “L. Vanvitelli”, Caserta, Italy
| | - Filomena Nazzaro
- Institute of Food Sciences, National Research Council (CNR-ISA), Avellino, Italy
| | - Pietro Ferraro
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
| | - Simonetta Grilli
- Institute of Applied Sciences and Intelligent Systems, National Research Council (CNR-ISASI), Pozzuoli, Italy
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Wu J, Qin N, Yuan B, Lin E, Bao D. Enhanced Pyroelectric Catalysis of BaTiO 3 Nanowires for Utilizing Waste Heat in Pollution Treatment. ACS APPLIED MATERIALS & INTERFACES 2018; 10:37963-37973. [PMID: 30360057 DOI: 10.1021/acsami.8b11158] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A novel catalytic effect of pyroelectric materials induced by a change in temperature, namely pyroelectric catalysis, was found to be attractive due to its ability to utilize waste heat in pollution treatment. In this work, the pyroelectric catalytic properties of BaTiO3 (BTO) nanowires synthesized by a template hydrothermal method have been thoroughly investigated. The nanowires with an elongated polar axis show a superior pyroelectric catalytic performance in comparison with the equiaxial nanoparticles. Our numerical simulation results with a finite element method indicate that the enhanced catalytic efficiency of BTO nanowires can be attributed to the higher pyroelectric potential. On the basis of the pyroelectric effect and our experimental results, a pyroelectric catalytic degradation mechanism has been proposed by taking into account the migration of charge carriers and the formation of reaction radicals. This study for enhancing the pyroelectric catalytic activity by using BTO nanowires may provide a facile, promising, and new reusable strategy for the catalytic degradation of organic dye pollutant by means of temperature variation. It is hoped that the present work gives a clear understanding of the mechanism of pyroelectric catalysis.
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Affiliation(s)
- Jiang Wu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Ni Qin
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Baowei Yuan
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Enzhu Lin
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Dinghua Bao
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering , Sun Yat-Sen University , Guangzhou 510275 , China
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Sanna S, Schmidt WG. LiNbO 3 surfaces from a microscopic perspective. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:413001. [PMID: 28737161 DOI: 10.1088/1361-648x/aa818d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A large number of oxides has been investigated in the last twenty years as possible new materials for various applications ranging from opto-electronics to heterogeneous catalysis. In this context, ferroelectric oxides are particularly promising. The electric polarization plays a crucial role at many oxide surfaces, and it largely determines their physical and chemical properties. Ferroelectrics offer in addition the possibility to control/switch the electric polarization and hence the surface chemistry, allowing for the realization of domain-engineered nanoscale devices such as molecular detectors or highly efficient catalysts. Lithium niobate (LiNbO3) is a ferroelectric with a high spontaneous polarization, whose surfaces have a huge and largely unexplored potential. Owing to recent advances in experimental techniques and sample preparation, peculiar and exclusive properties of LiNbO3 surfaces could be demonstrated. For example, water films freeze at different temperatures on differently polarized surfaces, and the chemical etching properties of surfaces with opposite polarization are strongly different. More important, the ferroelectric domain orientation affects temperature dependent surface stabilization mechanisms and molecular adsorption phenomena. Various ab initio theoretical investigations have been performed in order to understand the outcome of these experiments and the origin of the exotic behavior of the lithium niobate surfaces. Thanks to these studies, many aspects of their surface physics and chemistry could be clarified. Yet other puzzling features are still not understood. This review gives a résumé on the present knowledge of lithium niobate surfaces, with a particular view on their microscopic properties, explored in recent years by means of ab initio calculations. Relevant aspects and properties of the surfaces that need further investigation are briefly discussed. The review is concluded with an outlook of challenges and potential payoff for LiNbO3 based applications.
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Affiliation(s)
- Simone Sanna
- Institut für Theoretische Physik, Justus-Liebig-Universität Gießen, Gießen, Germany
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Song W, Chahal M, Celler GK, Jaluria Y, Reed GT, Jiang W. The influence of substrate on SOI photonic crystal thermo-optic devices. OPTICS EXPRESS 2013; 21:4235-4243. [PMID: 23481957 DOI: 10.1364/oe.21.004235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We investigate the influence of the substrate on a photonic crystal thermo-optic device on a silicon-on-insulator (SOI) platform. The substrate-induced thermo-optic tuning is obtained as a function of key physical parameters, based on a semi-analytic theory that agrees well with numeric simulations. It is shown that for some devices, the substrate's contribution to the thermo-optic tuning can exceed 10% for a heater located in the waveguide core and much higher for some other configurations. The slow response of the substrate may also significantly slow down the overall response time of the device. Strategies of minimizing the substrate's influence are discussed.
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Affiliation(s)
- Weiwei Song
- Department of Electrical and Computer Engineering, Rutgers University, Piscataway, NJ 08854, USA
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