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document
Daeichin, V. (author), Bera, D. (author), Raghunathan, S.B. (author), Shabanimotlagh, M. (author), Chen, Z. (author), Chen, C. (author), Noothout, E.C. (author), Vos, H.J. (author), Pertijs, M.A.P. (author), de Jong, N. (author), Verweij, M.D. (author)
This paper presents the design, fabrication and characterization of a miniature PZT-on-CMOS matrix transducer for real-time pediatric 3-dimensional (3D) transesophageal echocardiography (TEE). This 3D TEE probe consists of a 32 × 32 array of PZT elements integrated on top of an Application Specific Integrated Circuit (ASIC). We propose a...
journal article 2018
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Bera, D. (author), Raghunathan, S.B. (author), Chen, C. (author), Chen, Z. (author), Pertijs, M.A.P. (author), Verweij, M.D. (author), Daeichin, V. (author), Vos, H.J. (author), van der Steen, A.F.W. (author), de Jong, N. (author), Bosch, J.G. (author)
Until now, no matrix transducer has been realized for 3D transesophageal echocardiography (TEE) in pediatric patients. In 3D TEE with a matrix transducer, the biggest challenges are to connect a large number of elements to a standard ultrasound system, and to achieve a high volume rate (>200 Hz). To address these issues, we have recently...
journal article 2018
document
Chen, C. (author), Chen, Z. (author), Bera, Deep (author), Raghunathan, S.B. (author), Shabanimotlagh, M. (author), Noothout, E.C. (author), Chang, Z.Y. (author), Ponte, Jacco (author), Prins, Christian (author), Vos, H.J. (author), Bosch, J.G. (author), Verweij, M.D. (author), de Jong, N. (author), Pertijs, M.A.P. (author)
This paper presents a power-and area-efficient front-end application-specific integrated circuit (ASIC) that is directly integrated with an array of 32 × 32 piezoelectric transducer elements to enable next-generation miniature ultrasound probes for real-time 3-D transesophageal echocardiography. The 6.1 × 6.1 mm<sup>2</sup> ASIC, implemented...
journal article 2017
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Raghunathan, S.B. (author), Schouten, H.F. (author), Ubachs, W. (author), Ea Kim, B. (author), Gan, C.H. (author), Visser, T.D. (author)
Dynamic control of the direction of radiation of the light emanating from a subwavelength slit carved out of a thin metal film is experimentally demonstrated. This is achieved by selective excitation of the individual guided modes in the slit by setting the phase of three coherent laser beams. By changing the voltage across a piezoelement, we...
journal article 2013
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Raghunathan, S.B. (author), Schouten, H.F. (author), Visser, T.D. (author)
It was recently shown that so-called coherence vortices, singularities of the two-point correlation function, generally occur in partially coherent electromagnetic beams. We study the three-dimensional structure of these singularities and show that in successive cross sections of a beam a rich variety of topological reactions takes place. These...
journal article 2013
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Raghunathan, S.B. (author), Schouten, H.F. (author), Visser, T.D. (author)
We demonstrate that coherence vortices, singularities of the correlation function, generally occur in partially coherent electromagnetic beams. In successive cross sections of Gaussian Schell-model beams, their locus is found to be a closed string. These coherence singularities have implications for both interference experiments and correlation...
journal article 2012
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Raghunathan, S.B. (author), Gan, C.H. (author), Van Dijk, T. (author), Ea Kim, B. (author), Schouten, H.F. (author), Ubachs, W. (author), Lalanne, P. (author), Visser, T.D. (author)
We report a plasmon steering method that enables us to dynamically control the direction of surface plasmons generated by a two-mode slit in a thin metal film. By varying the phase between different coherent beams that are incident on the slit, individual waveguide modes are excited. Different linear combinations of the two modes lead to...
journal article 2012
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Raghunathan, S.B. (author), Van Dijk, T. (author), Peterman, E.J.G. (author), Visser, T.D. (author)
In trying to manipulate the intensity distribution of a focused field, one typically uses amplitude or phase masks. Here we explore an approach, namely, varying the state of spatial coherence of the incident field. We experimentally demonstrate that the focusing of a Bessel-correlated beam produces an intensity minimum at the geometric focus...
journal article 2010
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Raghunathan, S.B. (author), Budko, N.V. (author)
A generalization of the S-parameter retrieval method for finite three-dimensional inhomogeneous objects under arbitrary illumination and observation conditions is presented. The effective permittivity of such objects may be rigorously defined as a solution of a nonlinear inverse scattering problem. We confirm analytically and observe numerically...
journal article 2010
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Castagne, S. (author), Curran, R. (author), Rothwell, A. (author), Price, M. (author), Benard, E. (author), Raghunathan, S. (author)
A methodology to estimate the cost implications of design decisions by integrating cost as a design parameter at an early design stage is presented. The model is developed on a hierarchical basis, the manufacturing cost of aircraft fuselage panels being analysed in this paper. The manufacturing cost modelling is original and relies on a genetic...
journal article 2008
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