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Mu and epsilon near zero metamaterials for perfect coherence and new antenna designs

OPTICS EXPRESS 2014年第8期22卷 9107-9114页

作者： Yang, Jing Jing Francescato, Yan Maier, Stefan A. Mao, Fuchun Huang, Ming Yunnan Univ Wireless Innovat Lab Kunming 65009 Peoples R China Univ London Imperial Coll Sci Technol & Med Blackett Lab London SW7 2AZ England

Wave interference is a fundamental physical phenomenon. Traditionally, the coherent effect of two identical point sources only takes place when the optical path is an integer number of wavelengths. In this paper, we show that mu and epsilon near zero (MENZ) metamaterials can be used to realize a perfectly constructive and isotropic interference. No matter how many point sources are embedded in the MENZ region, the wavefronts overlap perfectly. This translates into a total relaxation of the conventional condition for coherence enabled by the apparent infinite wavelength of the fields within MENZ metamaterials. Furthermore, we investigate crucial parameters such as the shape and size of the MENZ region. We demonstrate that flat sided geometries give rise to constructive interference beams serving as a powerful design mean. We also reveal the importance of relying on deeply sub-wavelength MENZ volumes as larger sizes increase the impedance and therefore reduce the output power of the device. The proposed concepts bear significance for current trends in antenna design which are inspired by the recent developments of electromagnetic metamaterials. Moreover, the perfect coherence effect can be appealing for power combiners, especially in the terahertz where sources are dim, as the irradiation intensity scales with the square of the number of embedded sources. (C) 2014 optical Society of America

关键词： Constructive interference Invisibility cloaks Light transmission optical metamaterials Transformation optics Wave propagation

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current developments in Lens design and optical engineering XIII

Current Developments in Lens Design and Optical Engineering ...

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current developments in Lens design and optical engineering XIII

ISBN: (纸本)9780819492036

The proceedings contain 41 papers. The topics discussed include: novel global optimization algorithms: binary construction and the saddle-point method;finding starting points analytically for optical system optimization;reflaxicon objectives for imaging;digital optical microscope as a sampled imaging system: mathematical description, camera selection and focusing;graphically selecting optical components and housing material for color correction and passive athermalization;design and implementation of multi-layer and multi-bit micro holographic optical data storage employing blue lasers;using micro-projectors to realize large screen head-up display;fly-cutting and testing of freeform optics with sub-μm shape deviations;hybrid polishing of fused silica glass with bound-abrasive polishers in conjunction with vibration;and ultrastable mirrors made from diamond reinforced SiC composites for high precision and power applications.

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Proof-of-concept demonstration of a miniaturized multi-resolution refocusing imaging system using an electrically tunable lens 15

Proof-of-concept demonstration of a miniaturized multi-resol...

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Conference on current developments in Lens design and optical engineering XV

作者： Smeesters, L. Belay, G. Y. Ottevaere, H. Meuret, Y. Vervaeke, M. Van Erps, J. Thienpont, H. Vrije Univ Brussel Fac Engn Dept Appl Phys & Photon TONA Brussels Photon Team B PHOT B-1050 Brussels Belgium

ISBN: (纸本)9781628412192

Refocusing multi-channel imaging systems are nowadays commercially available only in bulky and expensive designs. Compact wafer-level multi-channel imaging systems have until now only been published without refocusing mechanisms, since classical refocusing concepts could not be integrated in a miniaturized configuration. This lack of refocusing capabilities limits the depth-of-field of these imaging designs and therefore their application in practical systems. We designed and characterized a wafer-level two-channel multi-resolution refocusing imaging system, based on an electrically tunable liquid lens and a design that can be realized with wafer-level mass-manufacturing techniques. One wide field-of-view channel (2x40 degrees) gives a general image of the surroundings with a lower angular resolution (0.078 degrees), whereas the high angular resolution channel (0.0098 degrees) provides a detailed image of a small region of interest with a much narrower field-of-view (2x7.57 degrees). The latter high resolution imaging channel contains the tunable lens and therefore the refocusing capability. The performances of this high resolution imaging channel were experimentally characterized in a proof-of-concept demonstrator. The experimental and simulated depth-of-field and resolving power correspond well. Moreover, we are able to obtain a depth-of-field from 0.25m until infinity, which is a significant improvement of the current state-of-the-art static multi-channel imaging systems, which show a depth-of-field from 9m until infinity. Both the high resolution and wide field-of-view imaging channels show a diffraction-limited image quality. The designed wafer-level two-channel imaging system can form the basis of an advanced three-dimensional stacked image sensor, where different image processing algorithms can be simultaneously applied to the different images on the image sensor.

关键词： lens system design adaptive optics tunable lens refocusing imaging systems modulation transfer function miniature camera optics proof-of-concept demonstration

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Materials science and design for germanium monolithic light source on silicon

Materials science and design for germanium monolithic light ...

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作者： Cai, Yan Massachusetts Institute of Technology

学位级别：博士

Germanium (Ge) is an optically active material with the advantages of Si-CMOS compatibility and monolithic integration. It has great potential to be used as the light emitter for Si photonics. Tensile strain and n-type doping are two key properties in Ge to achieve optical gain. This thesis mainly focuses on: (1) physical understandings of the threshold behavior of Ge-on-Si bulk laser and the temperature dependent performance; (2) process developments to grow and planarize the epitaxial Ge on Si in oxide trenches and corners; (3) introduction of n-type dopant into Ge-on-Si thin films while studying the threading dislocation behavior in n-Ge during annealing; (4) design an external cavity Ge laser integrated with Si waveguides for a low threshold current and single mode operation. Heavy n-type doping was observed to change the Ge electronic band structure by band gap narrowing effect. We also found a failure of using a simple Drude model to explain free carrier absorption in n-Ge. We modified the optical gain simulation based on the above two observations in Ge. We found a broad gain bandwidth of ~ 200 nm from 1550 nm to 1750 nm and a higher net materials gain. We predicted a theoretical lasing threshold current density of 5~10 kA/cm² in the bulk Ge laser device with the n-type doping of mid-10¹⁹ cm-³ at room temperature. We also predicted the Ge laser device would have better temperature stability regarding the threshold current compared to the III-V laser. Single crystalline Ge was epitaxial grown on Si in oxide trenches using ultra high vacuum chemical vapor deposition. The selective growth lead to the faceting in Ge because of the different growth rates of crystal orientations. We developed a suitable photolithography and oxide etch process to get the vertical oxide sidewall for Ge trench filling. We also tested the Ge growth in the T-shape corners to improve the reflectivity at the waveguide end. The T-shape structure was also useful for the Ge/Si waveguide coup

关键词： Materials Science and engineering

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Recent advancements in optofluidics-based single-cell analysis: optical on-chip cellular manipulation, treatment, and property detection

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LAB ON A CHIP 2014年第7期14卷 1230-1245页

作者： Huang, Nien-Tsu Zhang, Hua-li Chung, Meng-Ting Seo, Jung Hwan Kurabayashi, Katsuo Natl Taiwan Univ Dept Elect Engn Taipei 10617 Taiwan Natl Taiwan Univ Grad Inst Biomed Elect & Bioinformat Taipei 10617 Taiwan Nantong Univ Sch Mech Engn Nantong 226019 Peoples R China Univ So Calif Dept Biomed Engn Los Angeles CA 90007 USA Hongik Univ Dept Mech & Syst Design Engn Seoul 121791 South Korea Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA

Cellular analysis plays important roles in various biological applications, such as cell biology, drug development, and disease diagnosis. Conventional cellular analysis usually measures the average response from a whole cell group. However, bulk measurements may cause misleading interpretations due to cell heterogeneity. Another problem is that current cellular analysis may not be able to differentiate various subsets of cell populations, each exhibiting a different behavior than the others. Single-cell analysis techniques are developed to analyze cellular properties, conditions, or functional responses in a large cell population at the individual cell level. Integrating optics with microfluidic platforms provides a well-controlled microenvironment to precisely control single cell conditions and perform non-invasive high-throughput analysis. This paper reviews recent developments in optofluidic technologies for various optics-based single-cell analyses, which involve single cell manipulation, treatment, and property detection. Finally, we provide our views on the future development of integrated optics with microfluidics for single-cell analysis and discuss potential challenges and opportunities of this emerging research field in biological applications.

关键词： cell heterogeneity Cells Single-Cell Analysis Integrated optics Microfluidics system-on-chip Disease diagnosis cell population

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The rectenna device: From theory to practice (a review)

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MRS ENERGY & SUSTAINABILITY 2014年第1期1卷 1页

作者： Donchev, Evgeniy Pang, Jing S. Gammon, Peter M. Centeno, Anthony Xie, Fang Petrov, Peter K. Breeze, Jonathan D. Ryan, Mary P. Riley, D. Jason Alford, Neil McN. Imperial Coll London Dept Mat London SW7 2AZ England Univ Warwick Sch Engn Coventry CV4 7AL W Midlands England Malaysia Japan Int Inst Technol iKhoza Nanocharacterizat Struct Control & Proc Kuala Lumpur 54100 Malaysia

This review article provides the state-of-art research and developments of the rectenna device and its two main components - the antenna and the rectifier. Furthermore, the history, efficiency trends, and socioeconomic impact of its research are also featured. The rectenna (RECTifying antENNA), which was first demonstrated by William C. Brown in 1964 as a receiver for microwave power transmission, is now increasingly researched as a means of harvesting solar radiation. Tapping into the growing photovoltaic market, the attraction of the rectenna concept is the potential for devices that, in theory, are not limited in efficiency by the Shockley-Queisser limit. In this review, the history and operation of this 40-year old device concept are explored in the context of power transmission and the ever increasing interest in its potential applications at terahertz frequencies, through the infrared and visible spectra. Recent modeling approaches that have predicted controversially high efficiency values at these frequencies are critically examined. It is proposed that to unlock any of the promised potential in the solar rectenna concept, there is a need for each constituent part to be improved beyond the current best performance, with the existing nanometer scale antennas, the rectification and the impedance matching solutions all falling short of the necessary efficiencies at terahertz frequencies. Advances in the fabrication, characterization, and understanding of the antenna and the rectifier are reviewed, and common solar rectenna design approaches are summarized. Finally, the socioeconomic impact of success in this field is discussed and future work is proposed.

关键词： efficiency nanostructure optical

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Recent developments in magneto-optic garnet-type thin-film materials synthesis

Recent developments in magneto-optic garnet-type thin-film m...

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7th International Conference on Materials for Advanced Technologies, ICMAT 2013

作者： Nur-E-Alam, Mohammad Vasiliev, Mikhail Kotov, Viacheslav Alameh, Kamal Electron Science Research Institute Edith Cowan University 270 Joondalup Drive Joondalup WA 6027 Australia Institute of Radio Engineering and Electronics RAS 11 Mohovaya St Moscow 125009 Russia

Magneto-optic (MO) garnets are used in a range of applications in nanophotonics, integrated optics, communications and imaging. Bi-substituted iron garnets of different compositions are the most useful class of materials in applied magnetooptics due to their excellent MO properties (large Faraday effect) and record-high MO figure of merit among all semitransparent dielectrics. It is highly desirable to synthesise garnets which possess simultaneously a high MO figure of merit and large uniaxial magnetic anisotropy. However, the simultaneous optimization of several material properties and parameters can be difficult in single-layer garnet thin films, and it is also challenging to prepare films with high bismuth content using physical vapor deposition technologies. To meet the current challenge of developing next-generation functional MO materials, we design, develop and demonstrate the functionality of new magnetostatically-altered all-garnet multilayer heterostructures using two different garnet materials of dissimilar anisotropy types (out-of-plane and almost-inplane). The multilayer structures possess simultaneously a high MO figure of merit and large uniaxial magnetic anisotropy together with low coercivity, if each of the layers is optimized in composition and annealed correctly. We prepare thin-film heterostructures by sandwiching a MO garnet layer with almost in-plane magnetization in-between two MO garnet layers with out-of-plane magnetization using RF sputtering. We apply customised high-temperature oven annealing processes (optimized in temperature and process durations after running many trials) for the as-deposited (amorphous) garnet multilayers to obtain the crystalline garnet phase in every layer. These structures then possess simultaneously a high optical/MO quality and low coercivity, which is very attractive for the development of magnetic photonic crystals, sensing devices and ultra-fast switches. Based on Bi-substituted ferrite garnets grown on garn

关键词： Magnetos

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Man versus Machine: a Lens design Challenge

Man versus Machine: a Lens Design Challenge

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Conference on current developments in Lens design and optical engineering XIV

作者： Dilworth, Donald C. Shafer, David Optical Systems Design Inc. (United States) David Shafer Optical Design (United States)

After a generation of writing and improving lens design software, it is time to assess where we are. Specifically, can a modern program compete with, or surpass, the best human designers? Here we describe a friendly c... 详细信息

ISBN: (纸本)9780819496911

关键词： Lens design global optimization optimization algorithms aberration theory

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Polarization fields for understanding polarization aberrations in optical imaging systems

Polarization fields for understanding polarization aberratio...

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Conference on current developments in Lens design and optical engineering XIV

作者： Sasian, Jose Univ Arizona Coll Opt Sci Tucson AZ 85721 USA

This paper provides a set of polarization aberration fields that are useful for understanding polarization aberrations in optical imaging systems. The aberration function of a plane symmetric system is used to build t... 详细信息

ISBN: (纸本)9780819496911

关键词： polarization aberrations optical imaging systems

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Multiagent System in Automatic Light Power Balance in optical Networks

Multiagent System in Automatic Light Power Balance in Optica...

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Conference on current developments in Lens design and optical engineering XIV

作者： Slapak, Martin Hula, Milislav CESNET Ale Prague 16000 6 Czech Republic

ISBN: (纸本)9780819496911

This article deals with automatic power balancing along an optical line. For optimal transmission of an optical signal it is important to achieve certain parameters such as the signal to noise ratio orchromatic dispersion and also the sufficient output power level of in-line amplifiers. Pump diodes in amplifiers suffer from aging of material and therefore the driving current of pump diodes has to be accordingly increased to achieve the same gain as in the moment when the pump diodes were new. The use of a minimal required driving current leads to the longer lifetime of optical pumps. Therefore an automatic power balance is one of the methods used to achieve these goals.

关键词： Multiagent system automatic power balance gain control

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