Here you will find presentations given at COMSOL Conferences around the globe. The presentations explore the innovative research and products designed by your peers using COMSOL Multiphysics. Research topics span a wide array of industries and application areas, including the electrical, mechanical, fluid, and chemical disciplines. Use the Quick Search to find presentations pertaining to your application area.

Modeling of an Optical Black Hole with True Gaussian Beam Incidence

X. Ni[1], A. Kildishev[1], E. Narimanov[1], and L. Prokopeva[2]
[1]Purdue University, West Lafayette, IN, USA
[2]Russian Academy of Sciences, Novosibirsk, Russia

We model an ideal optical black hole device in COMSOL Multiphysics as an electromagnetic scattering problem. The device is illuminated with a Gaussian beam which is focused at a fixed position in horizontal direction (x0) and different positions in vertical direction (y0). The device is modeled as a cylindrical system with a gradient-index shell and absorbing core. Using the classical paraxial ...

Time-Resolved Optical Tomography in Preclinical Studies: Propagation of Excitation and Fluorescence Photons.

F. Nouizi[1], R. Chabrier[1], M. Torregrossa[2], and P. Poulet[1]
[1]Laboratoire d’Imagerie et de Neurosciences Cognitives, Straßbourg, France
[2]Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection, France

We present time-resolved methods that rely on near-infrared photons to image the optical properties and distribution of fluorescent probes in small laboratory animals. The coupled diffusion equations of excitation and fluorescence photons in highly scattering tissues were solved using the three-dimensional Finite Element Method (FEM) provided by COMSOL. The computed results allowed to yield ...

Dielectric Adaptive Optical Gels

R. Eisenschmid [1],
[1] OPTIMA pharma GmbH, Schwäbisch Hall, Germany

Adaptive Optics is common sense, since many people use digital cameras with electromechanical iris actors on elastic autofocus lenses. This project tries to create a COMSOL Multiphysics based mathematical model of adaptive optics with electrostatically induced deformation of dielectric gels. Upper and lower sides of a lens (dielectric conductive gel) are coated by transparent conductive films, i ...

Near-fields in Arrays of Triangular Particles: Coupling Effects and Field Enhancements

M. Goncalves[1], T. Makaryan[2], G. Papageorgiou[3], U. Herr[3], and O. Marti[1]
[1]Ulm University - Inst. of Experimental Physics, Ulm, Germany
[2]Yerevan State University, Yerevan, Armenia
[3]Ulm University - Institute of Micro and Nanomaterials, Ulm, Germany

Surface enhanced Raman scattering (SERS) investigations of silver and gold triangular nanoparticles reveal strong field enhancements at the corners of the particles. Though the measurements were done at wavelengths far from the surface-plasmon resonance of the particles, large field enhancements can be generated by near-field coupling between the triangular particles and smaller metal ...

A Comparison of Mass Reduction Methods for Silicon-on-Oxide (SOI)-based Micromirrors

H. J. Hall [1], L. A. Starman [1],
[1] Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, USA

Beam steering and adaptive optics micromirror applications commonly demand optically flat surfaces with minimal mass. When reflective coatings (usually metallic Au or Al) are applied to micromirror surfaces in order to meet optical reflectivity requirements the resulting film stress (usually tensile) can be substantial. The mass of the mirror can be a limiting factor in the dynamic performance. ...

Optimized Illumination Directions of Single-Photon Detectors Integrated with Different Plasmonic Structures

M. Csete[1], Á. Sipos[1], A. Szalai[1], G. Szabó[1]
[1]Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary

The optimal orientations of different single-photon detector designs were determined by COMSOL software package. Absorption of niobium-nitride (NbN) stripes in two different (p=220 nm, 3p=660 nm) periodic patterns integrated with plasmonic elements was studied. In OC-SNSPDs consisting of ~quarter-photon-wavelength nano-cavity the optimum direction is perpendicular incidence onto NbN stripes in P ...

Coupling Picosecond Terahertz Pulses to a Scanning Tunneling Microscope

P. H. Nguyen [1], C. Rathje [2], G. J. Hornig [1], V. Jelic [1], C. Ropers [2], F. A. Hegmann [1],
[1] University of Alberta, Edmonton, AB, Canada
[2] 4th Physical Institute, University of Göttingen, Göttingen, Germany

Probing ultrafast processes over subpicosecond and picosecond time scales provides fundamental insight into the nature of materials. We have experimentally demonstrated terahertz (THz)-pulse-induced tunneling in a scanning tunneling microscope (THz-STM) to image surfaces with simultaneous nanometer spatial resolution and subpicosecond time resolution [1]. However, the exact mechanism by which ...

Multiphysics Modeling of Electro-Optic Devices

J. Toney
Srico, Inc.
Columbus, OH

Designers of electro-optic modulators and related devices often use separate tools to study the optical and electrical portions of the device. The flexibility of COMSOL Multiphysics makes it possible to construct unified models of EO phenomena including realistic waveguide profiles and anisotropic material properties. We demonstrate the use of the RF Module to compute both RF and optical ...

Periodic Near-field Enhancement on Metal-Dielectric Interfacial Gratings at Optimized Azimuthal Orientation

M. Csete[1,2], X. Hu[1], A. Sipos[2], A. Szalai[2], A. Mathesz[2], and K. Berggren[1]

[1]Research Laboratory of Electronics, Nanostructures Laboratory, Massachusetts Institute of Technology, Massachusetts, USA
[2]Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary

The effect of plasmon-wavelength scaled gratings on the surface plasmon resonance is studied experimentally and theoretically. The model samples are multi-layers containing laser fabricated gratings at bimetal-polymer interfaces. Dual-angle dependent surface plasmon resonance measurements are performed illuminating the samples by monochromatic light in Kretschmann arrangement. The double ...

The Effect of Space Charge due to the Auto-Ionization of Neutral, Hydrogenic States in Point-Contact Germanium Detectors at MilliKelvin Temperatures - new

D. Faiez[1], N. Mirabolfathi[1], B. Sadoulet[1], K. M. Sundqvist[2]
[1]Department of Physics, University of California - Berkeley, Berkeley, CA, USA
[2]Department of Electrical & Computer Engineering, Texas A&M University, College Station, TX, USA

A class of semiconducting detectors, operated at temperature T~50mK, has direct application to the search for dark matter particle, when are able to simultaneously measure both the ionization and phonons created by particle interactions. We explore the effect of space charge accumulation in a germanium p-type point contact detector which arises due to the auto-ionization of hydrogenic ...