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.

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 ...

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 ...

Optimization of Micro-Structured Waveguides in Lithium Niobate (Z-Cut) - new

H. Karakuzu[1], M. Dubov[1], S. Boscolo[1]
[1] Aston University, Birmingham, UK

We present an optimization procedure to improve the propagation properties of the depressed-cladding, buried micro-structured waveguides formed in a z-cut lithium niobate (LN) crystal by high repetition rate femtosecond (fs) laser writing. It is shown that the propagation wavelength for which the confinement losses of ordinary (O) and extraordinary ordinary (E) polarizations are below 1 dB/cm ...

FEM Simulations of Rod-Type Photonic Crystal Slabs as Resonant Microsystems for Optical Gas Sensors

C. Kraeh, and H. Hedler
Siemens AG, Munich
Munich, Germany

We are developing a solid state gas sensor that combines a small form factor with the high sensitivity of optical gas detection. The gas sensor is based on an optical resonant microsystem that is penetrated by gas molecules. This microsystem consists of an array of vertical rods in air forming a photonic crystal. Light propagates through the photonic crystal along a line defect waveguide. For ...

Optimization of 3D Layered Metal-Dielectric Stacks (MDS) for Near-Field Fluorescence Imaging

P.S. Tan[1], K. Elsayad[2], K. Heinze[1]
[1]Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
[2]Research Institute of Molecular Pathology (IMP), Vienna, Austria

Nano-structures consisting of layered metal-dielectric stacks (MDSs) can be designed to have evanescent transmission and reflection coefficients that oscillate as a function of transverse wavevector and frequency. However, these structures always suffer from the material losses and surface roughness that are detrimental to image reconstruction. As such, we propose an optimized planar anisotropic ...

Super-resolving Properties of Metallodielectric Stacks

N. Katte[1], J. Haus[1], J.B. Serushema[1], and M. Scalora[2]
[1]University of Dayton, Dayton, OH, USA
[2]Charles M. Bowden Research Center, Redstone Arsenal, AL, USA

We show that diffraction can be suppressed in a one-dimensional metallodielectric stack (MDS) at visible wavelengths to achieve super-resolution imaging. In our calculations we use two popular techniques, which can be adapted to investigate the imaging properties of MDSs. The two methods are the transfer matrix method (TMM) and the Finite element method based software, COMSOL Multiphysics. The ...

Design of Tunable Metamaterial Operating Near 90 GHz

K. Tarnowski[1], W. Salejda[1]
[1]Institute of Physics, Wroclaw University of Technology, Wroclaw, Poland

Currently there is much interest in electromagnetic metamaterials [1-9]. In our work we have focused on design of tunable metamaterial which can be made within available technology. In proposed design we use metallic split-ring resonators and thin-wires (Figure 1). Moreover we have decided to introduce nematic liquid crystal layer in design to obtain tunability (Figure 2). One can control ...

Purcell Effect via Numerical Simulation - new

I. Zabkov [1], V. Klimov[1], A. Pavlov[1], D. Guzatov[2]
[1]All-Russia Research Institute of Automatics (VNIIA), Moscow, Russia
[2]Yanka Kupala State University of Grodno, Grodno, Belarus

As it is known nano-sized emitters (such as atoms, quantum dots and point defects in diamonds) interaction with nano-environment leads to drastic changes of their decay rate and therefore lifetime (Purcell effect). To calculate the influence in general one needs to solve equations of quantum electrodynamics. However in weak interaction limit these emitters can be considered as point electric ...

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 ...

The Optical Properties of a Truncated Spherical Cavity Embedded in Gold

A. Pors[1], O. Albrektsen[2], S.I. Bozhevolnyi[2], and M. Willatzen[1]
[1]Mads Clausen Institute, University of Southern Denmark, Sønderborg, Denmark
[2]Institute of Sensors, Signals and Electrotechnics, University of Southern Denmark, Odense, Denmark

The use of plasmonic effects to dramatically enhance the electromagnetic field near the surface of a metallic nanostructured surface has grown into a large research area in the effort to take advantage of the surface enhanced field. In this paper the electromagnetic field near a nano-sized truncated spherical cavity embedded in a gold substrate is investigated and modeled in 3D with COMSOL ...