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Laser Optics 2000 Conference

作者： Glova, AF Lebedev, EA Lysikov, AY Musyona, EI Shchetnikov, SB Troitsk Inst Innovat & Fus Res RU-142092 Troitsk Moscow Russia

Experimental investigations of radiation parameters of 2d arrays of waveguide CO2 lasers synchronized by in-cavity spatial filter method are carried out. Phase locked regime in a system of two ring waveguide CO2 laser... 详细信息

ISBN: (纸本)0819440434

关键词： phase locking waveguide lasers 2d array ring cavity locking band

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Reflectionless lossy Metasurface for Full Control of Electromagnetic Wave Transmission

Reflectionless lossy Metasurface for Full Control of Electro...

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IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IEEE MTT-S IMWS-AMP 2015)

作者： Zhu, Bo O. Nanjing Univ Sch Elect Sci & Engn Nanjing Jiangsu Peoples R China

ISBN: (纸本)9781479964505

The metasurface is a two dimensional array of subwave-length scatters [1]. It can be characterized by the surface impedance. Inspired by the equivalent principle, surface magnetic impedance is introduced into the metasurface to generate effective surface magnetic current under excitation [2]. It is proved that when the surface electric and magnetic impedance are passive and lossless, the transmission magnitude and phase can be tuned independently and fully [3].

关键词： electromagnetic wave scattering electromagnetic wave transmission surface electromagnetic waves surface magnetism 2d array reflectionless lossy metasurface subwave-length scatters surface electric impedance surface magnetic current surface magnetic impedance transmission magnitude Electromagnetic devices Impedance Metamaterials Propagation losses Surface impedance Surface treatment Surface waves

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High-Power VCSEL arrays with Customized Beam divergence for 3d Sensing Applications 23

High-Power VCSEL Arrays with Customized Beam Divergence for ...

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Conference on Vertical-Cavity Surface-Emitting Lasers XXIII

作者： Okur, Serdal Scheller, Maik Seurin, Jean-Francois Miglo, Alexander Xu, Guoyang Guo, dingkai Van Leeuwen, Robert Guo, Baiming Othman, Hasan Watkins, Laury Ghosh, Chuni Ams AG 1 Elect Dr Mercerville NJ 08619 USA

ISBN: (数字)9781510625198

ISBN: (纸本)9781510625198

The demand for highpower verticalcavity surfaceemitting laser (VCSEL) arrays is increasing continuously due to the growing market for 3d sensing solutions. In these applications (e.g. face recognition or driveassistance systems), the distances of the objects of interest vary by orders of magnitude. For this reason, a flexible tailoring of the beam divergence is desired. In this work, we discuss methods to tune the emitted beam profile by only optimizing the epitaxial structure of a VCSEL. We show results of VCSEL arrays with beam divergences ranging between similar to 10 degrees and 45 degrees. This technique is also power scalable and multi-watt VCSEL arrays can be realized.

关键词： Semiconductor lasers vertical-cavity surface-emitting lasers (VCSELs) high efficiency high-power 2d array beam divergence brightness

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Modeling nanoscale ink transport in dip pen nanolithography™

Modeling nanoscale ink transport in dip pen nanolithography™

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2nd Conference on Micro (MEMS) and Nanotechnologies for Space, defense, and Security

作者： Nafday, Omkar A. Vaughn, Mark W. Haaheim, Jason Weeks, Brandon L. NanoInk Inc 8025 Lamon Ave Skokie IL 60077 USA Texas Tech Univ Lubbock TX 79409 USA

ISBN: (纸本)9780819471505

In dip Pen Nanolithography (R) (dPN (R)), ink transport is reported to occur through the water meniscus formed between the AFM tip and the substrate by capillary condensation. It is imperative to understand the ink transport mechanisms in order to develop reliable commercial applications of dPN, and NanoInk is at the forefront of these efforts. In this work, we model the dot patterns of 16-Mercaptohexadecanoic acid (MHA) created by evaporative coating of a 1d 18 cantilever array and perform predictive modeling with solution based MHA cantilever inking results. We extend the functionality of the NanoInk 2d nano Printarray (TM) (2d array) by measuring the uniformity of 1-octadenethiol (OdT) dot patterns created. Further, we try to quantify the uniformity of patterns created by the 2d array, in a more statistically quantitative way. We do this by measuring the dot diameters of over 200 OdT ink patterns over a 1 x 1cm(2) area and examining the uniformity of the OdT vapor inking protocol developed.

关键词： 2d array 16-mercaptohexadecanoic acid dPN 1-octadecanethiol atomic force microscope

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Random Thinning of Segmented Annular arrays

Random Thinning of Segmented Annular Arrays

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IEEE Ultrasonics Symposium

作者： Godoy, G. Parrilla, M. Martin, C. J. Martinez, O. Ullate, L. G. Univ Jaen ETS Linares Linares Jaen 23700 Spain CSIC Inst Automat Ind E-28500 Madrid Spain

ISBN: (纸本)9781424402014

Two-dimensional (21)) array designs based on a squared matrix (S-M) distribution of elements require half wavelength (lambda/2) pitch for reducing grating lobes. From this condition, a 2d array for ultrasonic imaging will tipically contain several thousand of elements, which are much higher than the number of channels of present image systems. In contrast, segmented-annular (S-A) arrays have lower periodicity than squared patterns and allow increasing the inter-element distance surpassing one wavelength. Thus, the number of elements of the S-A array can be reduced by a factor of six with respect to the S-M array of equal size. However, for large apertures, this number is still a challenge for the existent technology, and thinning techniques are required. In this work, the results of applying the random thinning method to S-A arrays are analysed based on two different approaches: the array factor on the one hand, which considers omni-directional elements vibrating in continuous wave, and the real aperture in wide band on the other hand. Moreover, a comparison with the conventional S-M array of equivalent characteristics is also included. It is shown that the S-A array with pitch d=1.2 lambda overcomes the equivalent S-M array, producing beams which can be acceptable for ultrasonic image.

关键词： 2d array segmented annular array random thinning

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Growth of two-dimensional arrays of uncapped gold nanoparticles on silicon substrates

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BULLETIN OF MATERIALS SCIENCE 2008年第3期31卷 277-282页

作者： das, Anindya das, Soma Raychaudhuri, A. K. SN Bose Natl Ctr Basic Sci DST Unit Nanosci Kolkata 700098 India

A method of preparing large area patterned 2d arrays of uncapped gold (An) nanoparticles has been developed. The pattern has been formed. using self-assembly of uncapped An nanoparticles. The An nanoparticles were synthesized via toluene/water two phase systems using a reducing agent and colloidal solution of An nanoparticles was produced. These nanoparticles have been prepared without using any kind of capping agent. Analysis by TEM showed discrete An nanoparticles of 4 nm average diameter. AFM analysis also showed similar result. The TEM studies showed that these nanoparticles formed self-assembled coherent patterns with dimensions exceeding 500 nm. Spin coating on silicon substrate by suitably adjusting the speed can self-assemble these nanoparticles to lengths exceeding 1 mu m.

关键词： gold nanoparticles 2d array spin-coating self-assembly TEM AFM

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Comparison of different short-range sonar systems on real structures and objects

Comparison of different short-range sonar systems on real st...

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Oceans Aberdeen Conference

作者： Ehrhardt, M. degel, C. Becker, F. J. Peter, L. Hewener, H. Fonfara, H. Fournelle, M. Tretbar, S. Fraunhofer Inst Biomed Engn IBMT Div Ultrasound Joseph von Fraunhofer Weg 1 D-66280 Sulzbach Germany

ISBN: (纸本)9781509052783

In recent years, the ultrasound division of the Fraunhofer IBMT has developed and manufactured several imaging sonar systems for different visualization purposes. For short-range high-resolution imaging, three different concepts of sonar systems have been developed and transferred into demonstrators. The first one is a 128 element multibeam echosounder with a combined transmitting and receiving aperture. The second system is a volumetric imaging sonar based on a Mills Cross antenna configuration and the third system is a real-time capable, high-resolution 3d sonar camera with a matrix antenna consisting of 32 x 32 single transducer elements. After validating these systems on various phantoms in measurement tanks, more advanced measurements on real structures and objects were performed in order to evaluate and compare the imaging capabilities of the different sonar systems. In this work we present the results of these measurements together with an analysis of the specific advantages and disadvantages of the short-range imaging systems for different visualization tasks.

关键词： SONAR 2d array multibeam echosounder matrix array real-time 3d imaging volumetric sonar bathymetry inspection beamforming

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The Sonic Window: Second generation results

The Sonic Window: Second generation results

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Medical Imaging 2006 Conference

作者： Walker, William F. Fuller, Michael I. Brush, Edward V. Eames, Matthew d. C. Owen, Kevin Ranganathan, Karthik Blalock, Travis N. Hossack, John A. Univ Virginia Dept Biomed Engn Charlottesville VA 22903 USA Univ Virginia Dept Elect & Comp Engn Charlottesville VA 22903 USA PocketSon Inc Charlottesville VA USA PocketSon Inc Leesburg VA USA

ISBN: (纸本)0819461903

Medical Ultrasound Imaging is widely used clinically because of its relatively low cost, portability, lack of ionizing radiation, and real-time nature. However, even with these advantages ultrasound has failed to permeate the broad array of clinical applications where its use could be of value. A prime example of this untapped potential is the routine use of ultrasound to guide intravenous access. In this particular application existing systems lack the required portability, low cost, and ease-of-use required for widespread acceptance. Our team has been working for a number of years to develop an extremely low-cost, pocket-sized, and intuitive ultrasound imaging system that we refer to as the "Sonic Window." We have previously described the first generation Sonic Window prototype that was a bench-top device using a 1024 element, fully populated array operating at a center frequency of 3.3 MHz. Through a high degree of custom front-end integration combined with multiplexing down to a 2 channel PC based digitizer this system acquired a full set of RF data over a course of 512 transmit events. While initial results were encouraging, this system exhibited limitations resulting from low SNR, relatively coarse array sampling, and relatively slow data acquisition. We have recently begun assembling a second-generation Sonic Window system. This system uses a 3600 element fully sampled array operating at 5.0 MHz with a 300 micron element pitch. This system extends the integration of the first generation system to include front-end protection, pre-amplification, a programmable bandpass filter, four sample and holds, and four A/d converters for all 3600 channels in a set of custom integrated circuits with a combined area smaller than the 1.8 x 1.8 cm footprint of the transducer array. We present initial results from this front-end and present benchmark results from a software beamformer implemented on the Analog devices BF-561 dSP. We discuss our immediate plans for further int

关键词： ultrasound Ultrasonic Imaging medical imaging venous access 2d array dSP

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High-frequency low-noise ultrasonic detection arrays based on parallelly probing an etalon

High-frequency low-noise ultrasonic detection Arrays based o...

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IEEE Ultrasonics Symposium

作者： Huang, Sheng-Wen Hou, Yang Ashkenazi, Shai O'donnell, Matthew Univ Michigan Bio Med Engn Elect Engn Comp Sci Ann Arbor MI 48109 USA Univ Washington Bio Engn Seattle WA 98195 USA

ISBN: (纸本)9781424413836

For ultrasound detection systems using a thin polymer Fabry-Perot etalon, optically probing the etalon surface defines the acoustic array geometry and element size. We have previously demonstrated wide bandwidth signal detection (>40 MHz) and low noise-equivalent pressure (NEP) (2.1 kPa over a 50 MHz band) for an element on the order of 15 mu m In diameter. By integrating an etalon into a photoacoustic imaging system, high-resolution 3d Images were obtained. Nonetheless, the previous system Is limited for clinical applications because the etalon surface Is optically probed point by point and therefore a photodetector array cannot be used to increase frame rate. To move etalon detector technology toward real clinical applications, we have built and tested an ultrasound detection system with an optical end capable of parallel probing. A tunable laser (HP 8168F, Agilent Technologies) was used to drive an erbium-doped fiber amplifier (KPS-BT2-C-30-SLM-PM-PB-FA, Keopsys) to output light at 27 dBm at wavelengths between 1535 and 1565 nm. A lens collimated the light to probe a 6-mu m thick SU-8 etalon in parallel. The -3 dB tight spot on the etalon surface was 1.8 mm in diameter. The reflected light was guided onto a photodetector (818-BB-30A, Newport) with an active diameter of 100 mu m using a two-lens system mapping the active area to an element 28 mu m in diameter on the etalon surface. A 2d translation stage was used to carry the photodetector so that it could detect signals from different array elements. The photodetector output was amplified and then digitized using an oscilloscope (WaveSurfer 432, LeCroy). The NEP was estimated to be 7.0 kPa over a 50 Mliz band and the detection bandwidth was estimated to exceed 70 MHz. Using a single probe wavelength of 1550.6 nm, a 1d array with 81 elements and a 1.7 mm aperture length was formed to Image a 25 pin silver wire photoacoustically with laser pulse fluence of 27 mJ/cm(2) at 532 nm (Surelite I-20, Continuum). The final

关键词： etalon high-frequency ultrasound parallel detection 2d array photoacoustic optoacoustic

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Chip-scale integration of VCSEL, photodetector, and microlens arrays

Chip-scale integration of VCSEL, photodetector, and microlen...

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Conference on Optoelectronic Interconnects, Integrated Circuits, and Packaging

作者： Liu, Y Johnson, K Hibbs-Brenner, M Honeywell VCSEL Opt Prod Plymouth MN 55441 USA

ISBN: (纸本)0819443913

New generations of network application continue to demand component solutions of higher speed (10 Gbps and beyond) with good reliability and affordability. The potential of VCSEL arrays technology in meeting those demands has long been recognized and is being actively explored by many in the field. In this paper we present a few examples of VCSEL array based technology developments including monolithic integration of VCSELs an photodetector (Pd) in both 1d and 2d arrays, and their hybrid integration with micro-lens array and electronic integrated circuits for optical interconnects. As we explore to achieve more functionality through integration, we also emphasize on the merits of usability of the electrical and optical interfaces of the new components, and producibility and manufacturability aspects of the new technologies.

关键词： VCSEL Photodetector microlens 2d array smart pixel array monolithic integration heterogeneous integration Si ASIC data communications free space optical interconnects

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