The GST2 event took place at the campus of the University of Eastern Finland from June 23-17, 2014 and was hosted by Professor Jyrki Saarinen from UEF and coordinated by Dr. Noora Heikkilä from UEF.

During the GST2 the researchers were lectured on the basics of electromagnetic theory of optics, including waves in anisotropic media. Topics discussed were

  • the electromagnetic field of an electric dipole
  • plane wave expansion
  • the Huygens-Fresnel principle
  • Rayleigh-Sommerfeld diffraction formulae
  • Stratton-Chu formula
  • the Born approximation
  • Fresnel and Fraunhofer diffraction

The propagation of partially coherent light in free-space and through various types of optical interfaces was considered as well. The Extended Nijboer Zernike (ENZ) theory for focussing and imaging in systems of high NA was treated and diffraction limited imaging systems were studied. The general boundary value problem for the scattered field in periodic and non-periodic configurations was formulated. Approximate boundary conditions derived from the perfectly matched layer (PML) were studied.

Then rigorous numerical methods for solving the boundary value problem such as the Fourier Model Method (FMM) and the Finite Difference Time Domain (FDTD) and the Finite Element Method (FEM) were treated with examples.

Methodologies for solving inverse problems for diffractive structures were discussed. Optimization methods for designing diffractive structures were taught with special emphasis on resonant structures.

Throughout the week, the theory was clarified by examples using software such as e.g. Virtual Lab, Gsolver, Light Tools etc. During the final day hands-on training was given in the use of some of these packages.

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On the first day, Professor Jari Turunen from UEF talked about “Propagation in free space and though complex-amplitude transmittances.” Professor Tero Setälä from UEF continued on “Polarization and coherence of light, coherent-mode techniques” and Professor Jani Tervo from UEF concluded from “Analysis of periodic and non-periodic structure by the Fourier modal method.” During lunch and coffee breaks attendees had a possibility to discuss with each other and with the lecturers.

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On the second day, Professor Paul Urbach from TUD talked about “ENZ theory of focusing of light”. After lunch break Dr. Bernd Kleemann from Zeiss talked about “Broadband diffractive optics: design concepts and color correction.”

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On the third day, Dr. Bernd Kleemann continued on “Integral equation methods for gratings and the Reduced Basis Method.” After lunch break Dr. Pertti Pääkkönen presented research facilities at the Institute of Photonics (UEF). Then Professor Paul Urbach continued on “Rigorous analysis by diffractive structures by FDTD and FEM.”

The day was concluded by a Get-together party.

 

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Verslag GST2 011On the fourth day, Professor Frank Wyrowski from FSU started on “Diffractive-optics design with numerical examples. And after lunch break Dr. Christophe Sauvan from CNRS continued on “Analysis and design of subwavelength structures.”

The fifth and last day was open for ADOPSYS students only. The sessions took place in a computer class, where everybody had access to an own computer with optics software installed. Hands-on training on analysis and design of diffractive optics was started by Dr. Christophe Sauvan and, after lunch break, continued by professor Frank Wyrowski.