Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. EPFL thesis
  4. Dispersion Properties of Photonic Crystals and Silicon Nanostructures Investigated by Fourier-Space Imaging
 
Loading...
Thumbnail Image
doctoral thesis

Dispersion Properties of Photonic Crystals and Silicon Nanostructures Investigated by Fourier-Space Imaging

Jágerská, Jana  
2011

State-of-the-art nanophotonic devices based on semiconductor technology use total internal reflection or the photonic bandgap effect to reduce the waveguide core dimensions down to hundreds of nanometers, ensuring strong optical confinement within the scale of the wavelength. Within the framework of this thesis, we investigate the light propagation in such devices by direct experimental reconstruction of their dispersion relation ω (k), where ω is the optical frequency and k the wave vector of the supported modes. Knowledge of the dispersion relation provides us with comprehensive information about the guided field, including the number of supported modes, their phase and group velocity as well as the higher order dispersion. As a principal characterization tool, an original experimental technique referred as Fourier-space imaging is used. It is based on far-field analysis of optical signal radiated out of the plane of the structure, which makes it possible to retrieve accurately, non-invasively and in one step the complex dispersion of both the leaky and the truly guided optical modes. The latter is feasible provided that the device is equipped with vanishingly weak grating probes that scatter a small part of the guided light into the light cone. The Fourier-space imaging technique was applied to study the optical properties of a large number of nanophotonic devices, ranging from simple nanowire waveguides to complex photonic crystal structures. In the first part of the work, silicon-on-insulator slot waveguides, coupled ridge waveguides and nanowire waveguide arrays are addressed. Besides the phase and group index dispersion, we investigate the phenomenon of mode splitting in coupled systems, being able to probe the coupling lengths with an accuracy of ±50 nm. In the case of waveguide arrays, beam steering using both thermo-optic effect and wavelength tuning was demonstrated. Concerning the photonic crystal devices, we primarily focus on the phenomenon of slow light propagation in line-defect and coupled-cavity photonic crystal waveguides. The latter represent a special type of a waveguide, which allows for substantial optical signal retardation by evanescent coupling along a chain of photonic crystal cavities. The main motivation was to accurately measure the group index of the slow light modes and recognize the main factors limiting its maximum achievable value. Among others, experimental observation of dispersion curve renormalization, enhanced out-of-plane and back-scattering as well as light localization due to residual disorder were reported. Finally, a detailed experimental study of hollow-core photonic crystal structures intended for optical sensing applications is presented.

  • Files
  • Details
  • Metrics
Type
doctoral thesis
DOI
10.5075/epfl-thesis-4956
Author(s)
Jágerská, Jana  
Advisors
Houdré, Romuald  
Date Issued

2011

Publisher

EPFL

Publisher place

Lausanne

Thesis number

4956

Total of pages

155

Subjects

Nanophotonics

•

Photonic crystals

•

Dispersion

•

Slow light

•

Fourier-space imaging

•

Nanophotonique

•

Cristaux photoniques

•

Dispersion

•

Lumière lente

•

Imagerie de Fourier

EPFL units
LOEQ  
Faculty
SB  
School
ICMP  
Doctoral School
EDPO  
Available on Infoscience
January 6, 2011
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/62699
Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés