Surface integral equation analysis of quasi-optical launchers

Neilson, Jeffrey; Bunger, R.

doi:10.1109/tps.2002.801629

Cited by 56 publications

(25 citation statements)

References 9 publications

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“…The mode converter consists of a helical launcher with waveguide radius r wg = 2.85 mm, a quasi-parabolic smooth mirror, and two additional smooth mirrors. The mode converter design was evaluated using the electric field integral equation code Surf3d [21]. The results from these calculations are shown in Fig.…”

Section: Designmentioning

confidence: 99%

Operation of a Continuously Frequency-Tunable Second-Harmonic CW 330-GHz Gyrotron for Dynamic Nuclear Polarization

Torrezan

Shapiro

Sirigiri

et al. 2011

IEEE Trans. Electron Devices

161

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Abstract-The design and operation of a frequency tunable continuous-wave (CW) 330-GHz gyrotron oscillator operating at the second harmonic of the electron cyclotron frequency are reported. The gyrotron has generated 18 W of power from a 10.1-kV 190-mA electron beam working in a TE -4,3 cylindrical mode, corresponding to an efficiency of 0.9%. The measured start oscillation current over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high order axial modes TE -4,3,q , where q = 1 to 6. Also, the observed frequency range in the start current measurement is in reasonable agreement with the frequency range calculated from numerical simulations. The minimum start oscillation current of the device was measured to be 33 mA. A continuous tuning range of 1.2 GHz was observed experimentally via a combination of magnetic, voltage, and thermal tuning. The gyrotron output power and frequency stabilities were assessed to be ±0.4% and ±3 ppm, respectively, during a 110-hour uninterrupted CW run. Evaluation of the gyrotron microwave output beam pattern using a pyroelectric camera indicated a Gaussian-like mode content of 92% with an ellipticity of 28%. The gyrotron will be used for 500-MHz nuclear magnetic resonance (NMR) experiments with sensitivity enhanced by dynamic nuclear polarization (DNP).Index Terms-Dynamic nuclear polarization (DNP), nuclear magnetic resonance (NMR), second cyclotron harmonic, submillimeter wave, terahertz, tunable gyrotron.

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Section: Designmentioning

confidence: 99%

Operation of a Continuously Frequency-Tunable Second-Harmonic CW 330-GHz Gyrotron for Dynamic Nuclear Polarization

Torrezan

Shapiro

Sirigiri

et al. 2011

IEEE Trans. Electron Devices

161

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“…A technique widely used in microwave studies but rarely in optics is the transformation of the volume integral equation (VIE), readily obtained from Maxwell's equations, to a surface integral equation (SIE) formulation [15][16][17][18][19][20]. As the surface of an object scales with only the second power of its lateral dimension, this approach bears advantages especially for electrically large problems but also for rounded or irregular objects as surface discretization techniques prove extremely flexible [21].…”

Section: Introductionmentioning

confidence: 99%

Surface integral formulation for 3D simulations of plasmonic and high permittivity nanostructures

2009

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Among the most popular approaches used for simulating plasmonic systems, the discrete dipole approximation suffers from poorly scaling volume discretization and limited near-field accuracy. We demonstrate that transformation to a surface integral formulation improves scalability and convergence and provides a flexible geometric approximation allowing, e.g., to investigate the influence of fabrication accuracy. The occurring integrals can be solved quasi-analytically, permitting even rapidly changing fields to be determined arbitrarily close to a scatterer. This insight into the extreme near-field behavior is useful for modeling closely packed particle ensembles and to study "hot spots" in plasmonic nanostructures used for plasmon-enhanced Raman scattering.

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“…12 This procedure, while quite well-known in microwave studies, has only rarely been applied in optics. [13][14][15][16][17][18] In the first part of this paper we briefly introduce the most popular electromagnetic simulation routines, showing their range of application as well as their deficits. Next we show the main steps in deriving the proposed SIE formulation, including important post-processing procedures.…”

Section: -10mentioning

confidence: 99%

Modeling near-field properties of plasmonic nanoparticles: a surface integral approach

Kern

Martin

2009

SPIE Proceedings

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Recent developments in nanofabrication and optical near-field metrology have faced complementary modeling techniques with new demands. We present a surface integral formulation that accurately describes the extreme near-field of a plasmonic nanoparticle in addition to its far-field properties. Flexible surface meshing gives precise control over even complex geometries allowing investigation of the effects of fabrication accuracy and material homogeneity on a particle's optical response. Using this technique, the influence of a particle's symmetry and shape on surrounding "hot spots" of extremely large field enhancement is explored, giving insight into the mechanisms of surface enhanced Raman scattering and single-molecule detection techniques.

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Surface integral equation analysis of quasi-optical launchers

Cited by 56 publications

References 9 publications

Operation of a Continuously Frequency-Tunable Second-Harmonic CW 330-GHz Gyrotron for Dynamic Nuclear Polarization

Operation of a Continuously Frequency-Tunable Second-Harmonic CW 330-GHz Gyrotron for Dynamic Nuclear Polarization

Surface integral formulation for 3D simulations of plasmonic and high permittivity nanostructures

Modeling near-field properties of plasmonic nanoparticles: a surface integral approach

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