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Zimmerling, J.T. (author), Wei, L. (author), Urbach, H.P. (author), Remis, R.F. (author)We present a Krylov model-order reduction approach to efficiently compute the spontaneous decay (SD) rate of arbitrarily shaped 3D nanosized resonators. We exploit the symmetry of Maxwell’s equations to efficiently construct so-called reduced-order models that approximate the SD rate of a quantum emitter embedded in a resonating nanostructure....journal article 2016
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- Nemati, M. (author), Urbach, Paul (author), Bhattacharya, N. (author) journal article 2016
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Wei, L. (author), Urbach, Paul (author)The focal field properties of radially/azimuthally polarized Zernike polynomials are studied. A method to design the pupil field in order to shape the focal field of radially or azimuthally polarized phase vortex is introduced. With this method, we are able to obtain a pupil field to achieve a longitudinally polarized hollow spot with a depth of...journal article 2016
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Mann, Daniel (author), Nascimento Duplat, D. (author), Keul, Helmut (author), Möller, Martin (author), Verheijen, Marcel (author), Xu, M. (author), Urbach, Paul (author), Adam, A.J.L. (author), Buskens, Pascal (author)Au and Ag nanoshells are of interest for a wide range of applications. The plasmon resonance of such nanoshells is the property of interest and can be tuned in a broad spectral regime, ranging from the ultraviolet to the mid-infrared. To date, a large number of manuscripts have been published on the optics of such nanoshells. Few of these,...journal article 2016
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Ushakova, K. (author), Van den Berg, Q.Y. (author), Pereira, S.F. (author), Urbach, H.P. (author)Spot size reduction is demonstrated by printing focused spots from amplitude-modulated radially polarized light at the wavelength ? = 405 nm on a photoresist. Amplitude modulation is realized by ring illumination and by application of an optimized amplitude distribution function. Amplitude modulation is implemented via spatial light modulator,...journal article 2015
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Zhang, Y. (author), Shi, W. (author), Shen, Z. (author), Man, Z. (author), Min, C. (author), Shen, J. (author), Zhu, S. (author), Urbach, H.P. (author), Yuan, X. (author)Typically, metal particles are difficult to manipulate with conventional optical vortex (OV) tweezers, because of their strong absorption and scattering. However, it has been shown that the vortex field of surface plasmonic polaritons, called plasmonic vortex (PV), is capable of stable trapping and dynamic rotation of metal particles, especially...journal article 2015
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Leinders, S.M. (author), Westerveld, W.J. (author), Pozo, J. (author), Neer, P.L.M.J. (author), Snyder, B. (author), O'Brien, P. (author), Urbach, H.P. (author), de Jong, N. (author), Verweij, M.D. (author)With the increasing use of ultrasonography, especially in medical imaging, novel fabrication techniques together with novel sensor designs are needed to meet the requirements for future applications like three-dimensional intercardiac and intravascular imaging. These applications require arrays of many small elements to selectively record the...journal article 2015
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Nemati, M. (author), Loozen, G.B. (author), Van der Wekken, N. (author), Van de Belt, G. (author), Urbach, H.P. (author), Bhattacharya, N. (author), Kenjeres, S. (author)A preliminary comparative measurement between particle imaging velocimetry (PIV) and laser speckle contrast analysis (LASCA) to study pulsatile flow using ventricular assist device in a patient-specific carotid artery phantom is reported. These full-field optical techniques have both been used to study flow and extract complementary parameters....journal article 2015
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Strauch, M. (author), Livshits, I.L. (author), Bociort, F. (author), Urbach, H.P. (author)We show that wide-angle spectral imaging can be achieved with compact and cost-effective devices using Fabry-Pérot interferometers. Designs with a full field of view of 90°, in which the Fabry-Pérot interferometer is mounted either in front of an imaging lens system or behind a telecentric lens system, are presented and analysed. We show the...journal article 2015
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Roy, S. (author), Ushakova, K. (author), Van den Berg, Q. (author), Pereira, S.F. (author), Urbach, H.P. (author)A fast noninvasive method based on scattering from a focused radially polarized light to detect and localize subwavelength nanoparticles on a substrate is presented. The technique relies on polarization matching in the far field between scattered and spurious reflected fields. Results show a localization uncertainty of ?10?4?2 is possible for a...journal article 2015
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Reyes Reyes, A. (author), Hou, Z. (author), Van Mastrigt, E. (author), Horsten, R.C. (author), De Jongste, J.C. (author), Pijnenburg, M.W. (author), Urbach, H.P. (author), Bhattacharya, N. (author)We present a broadband quantum cascade laser-based spectroscopic system covering the region between 850 and 1250 cm?1. Its robust multipass cavity ensures a constant interaction length over the entire spectral region. The device enables the detection and identification of numerous molecules present in a complex gas mixture without any pre...journal article 2014
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Man, Z. (author), Du, L. (author), Min, C. (author), Zhang, Y. (author), Zhang, C. (author), Zhu, S. (author), Urbach, H.P. (author), Yuan, X.C. (author)Vector beams, which have space-variant state of polarization (SOP) comparing with scalar beams with spatially homogeneous SOP, are used to manipulate surface plasmon polarizations (SPPs). We find that the excitation, orientation, and distribution of the focused SPPs excited in a high numerical aperture microscopic configuration highly depend on...journal article 2014
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Nemati, M. (author), Presura, C.N. (author), Urbach, H.P. (author), Bhattacharya, N. (author)Continuous health monitoring has become a major theme of our aging society. Portable devices play an important role here. Many optical portable devices are susceptible to motion induced artifacts. We have performed an experimental study for detection of fluid pulsation based on multi-exposure speckle images, in presence of motion induced...journal article 2014
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Roy, S. (author), Assafrao, A.C. (author), Pereira, S.F. (author), Urbach, H.P. (author)Inspection tools for nano-particle contamination on a planar substrate surface is a critical problem in micro-electronics. The present solutions are either expensive and slow or inexpensive and fast but have low sensitivity because of limitations due to diffraction. Most of them are also substrate specific. In this article we report how Coherent...journal article 2014
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Zhang, Y. (author), Wu, X. (author), Min, C. (author), Zhu, S. (author), Urbach, H.P. (author), Yuan, X. (author)Monitoring the cells’ apoptosis progression could provide a valuable insight into the temporal events that initiate cell death as well as the potential for rescue of apoptotic cells. In this paper, we engineered a novel and robust method for monitoring apoptosis of tumor cells based on dynamic laser tweezers, using A549 and HeLa cell line as...journal article 2014
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El Gawhary, O. (author), Adam, A.J.L. (author), Urbach, H.P. (author)It is known that, at optical frequencies, a simple interface between a perfect dielectric and a real metal can sustain the propagation of surface plasmon polaritons only for P-polarized electromagnetic waves, being S-polarized surface plasmons are prohibited. In this work, we formally show that, strictly speaking, both polarization states are in...journal article 2014
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Konijnenberg, A.P. (author), Wei, L. (author), Kumar, N. (author), Couto Correa Pinto Filho, L. (author), Cisotto, L. (author), Pereira, S.F. (author), Urbach, H.P. (author)In several optical systems, a specific Point Spread Function (PSF) needs to be generated. This can be achieved by shaping the complex field at the pupil. The Extended Nijboer-Zernike (ENZ) theory relates complex Zernike modes on the pupil directly to functions in the focal region. In this paper, we introduce a method to engineer a PSF using the...journal article 2014
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Nemati, M. (author), Wijshoff, R.W.C.G.R. (author), Stijnen, J.M.A. (author), Van Tuijl, S. (author), Bergmans, J.W.M. (author), Bhattacharya, N. (author), Urbach, H.P. (author)We have performed an in vitro and in vivo study, based on laser speckle contrast analysis, to detect fluid pulsation in the presence of artifacts caused by the relative motion between the sample and the illumination source. We observe that the pulsation signal is clearly detectable for a range of motion amplitudes and oscillation frequencies;...journal article 2013
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Westerveld, W.J. (author), Pozo, J. (author), Leinders, S.M. (author), Yousefi, M. (author), Urbach, H.P. (author)We investigate directional couplers in silicon-on-insulator photonic technology. We theoretically and experimentally demonstrate a large coupling-induced phase delay that occurs when nearly all light is coupled from one waveguide to the other, i.e., when the coupler operates as a cross-coupler. We show that even a tiny asymmetry in the two...journal article 2013
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Haber, A. (author), Polo, A. (author), Maj, I. (author), Pereira, S.F. (author), Urbach, H.P. (author), Verhagen, M.H.G. (author)In this paper we experimentally demonstrate the proof of concept for predictive control of thermally induced wavefront aberrations in optical systems. On the basis of the model of thermally induced wavefront aberrations and using only past wavefront measurements, the proposed adaptive optics controller is able to predict and to compensate the...journal article 2013