Tag Archives: Shahraam Afshar

Generating whispering gallery mode spectra

9 March 2017:

A new publication from CNBP researchers (lead author Jonathan Hall pictured) presents a new model for generating whispering gallery mode spectra for multilayer microspheres.

The work has just been reported in the journal ‘Optics Express’ and is accessible online.

Journal: Optics Express.

Title: Unified theory of whispering gallery multilayer microspheres with single dipole or active layer sources.

Authors: Jonathan M. M. Hall, Tess Reynolds, Matthew R. Henderson, Nicolas Riesen, Tanya M. Monro, and Shahraam Afshar.

Abstract: The development of a fast and reliable whispering gallery mode (WGM) simulator capable of generating spectra that are comparable with experiment is an important step forward for designing microresonators. We present a new model for generating WGM spectra for multilayer microspheres, which allows for an arbitrary number of concentric dielectric layers, and any number of embedded dipole sources or uniform distributions of dipole sources to be modeled. The mode excitation methods model embedded nanoparticles, or fluorescent dye coatings, from which normalized power spectra with accurate representation of the mode coupling efficiencies can be derived. In each case, the emitted power is expressed conveniently as a function of wavelength, with minimal computational load. The model makes use of the transfer-matrix approach, incorporating improvements to its stability, resulting in a reliable, general set of formulae for calculating whispering gallery mode spectra. In the specific cases of the dielectric microsphere and the single-layer coated microsphere, our model simplifies to confirmed formulae in the literature.

Publication: Polymer based whispering gallery mode laser for biosensing applications

January Alexandre Francois Low Res Edit 00832015: Publication

Polymer based whispering gallery mode laser for biosensing applications

Alexandre François, Nicolas Riesen, Hong Ji, Shahraam Afshar and Tanya M. Monro

Appl. Phys. Lett. 106, 031104 (2015); http://dx.doi.org/10.1063/1.4905931

For the full article click here

Novel polymer functionalization method for exposed-core optical fiber

Roman Kosctecki Low Res Edit 0145

3 July 2014: Publication in Optical Society of America

Novel polymer functionalization method for exposed-core optical fiber

Authors: by Roman Kostecki,  Heike Ebendorff-Heidepriem, Shahraam Afshar,  GrantMcAdam, Claire Davis, and Tanya M. Monro

Abstract: We report on a one step functionalization process for optical
fiber sensing applications in which a thin film (∼50 nm) polymer doped
with sensor molecules is applied to a silica exposed-core fiber. The method
removes the need for surface attachment of functional groups, while
integrating the polymer, silica and sensor molecule elements to create a
distributed sensor capable of detecting an analyte of interest anywhere
along the fiber’s length. We also show that the thin film coating serves a
protective function, reducing deterioration in the transmission properties of
the silica exposed-core fiber, but increasing loss.