25 November 2011 Congratulations to New ICFO PhD graduate

Dr. Osamu Takayama


Thesis Committee

Dr Osamu Takayama graduated with a thesis on Dyakonov Surface Waves. Dr. Takayama received a master in Applied Science at Dalhousie University in Canada. In 2005 he joined ICFO and has been working on projects related to surface waves within Prof. Lluis Torner’s Nonlinear optical phenomena group.

Dr. Takayama presented a thesis titled ‘First Experimental Observation of Dyakonov Surface Waves’. His thesis was supervised by ICFO Group Leader and Director, Prof. Lluis Torner and UPC Prof. David Artigas

ABSTRACT:

A unique type of lossless surface electromagnetic wave, which takes place under stringent geometric and material conditions, was theoretically predicted by M. I. D\'yakonov in 1988. Since then numerous investigations have been conducted to study its nature, as well as the possible configurations and combinations of materials that would allow its observation. However, such observation remained elusive for more than two decades. The chief aim of this thesis was to tackle such a challenge, which we overcame in 2009.

The objective of this thesis dissertation is to report and to describe the theoretical background and the experimental procedure to observe this special kind of surface waves in an Otto-Kretschmann configuration. The method is based on a very careful sample identification and preparation, and in the subsequent observation of the reflected image of a laser beam from the interface that supports the surface waves introducing polarization conversion as a new spectroscopy technique of hybrid modes.

We start by giving a brief introduction of the different types of surface electromagnetic waves known to date, to the best of our knowledge. Then, we focus on the nature and detailed properties of Dyakonov surface waves. First, a theoretical analysis to clarify the nature of Dyakonov surface waves in Otto-Kretschmann configuration is presented. Second, the details of experimental observation are discussed in full detail.

Our Dyakonov surface waves were exited at the interface of a biaxial anisotropic crystal and an isotropic medium, and were experimentally observed using a KTP crystal as the birefringent medium, index matching liquid as the isotropic media and a ZnSe prism for coupling in Otto-Kretschmann configuration. The experimental results showed good agreement with theoretical predictions.

The thesis includes several important annexes, where theoretical derivations of the properties of the observed surface waves are given in detail. Also, investigations of the resonant transmission of light in structures supporting Dyakonov waves and the existence of Dyakonov surface waves in left-handed materials are reported in annexes. The motivation of the former is to show an application of the surface waves, while the motivation of the latter is to enhance their otherwise narrow angular existence domain. These extensions may be just the tip of an iceberg, as we discuss in the Conclusions and Outlook section.

THESIS COMMITTEE

President: Prof. Dumitru Mihalache, Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, ROMANIA

Secretary: Prof. Romain Quidant, ICREA Professor, ERC Starting Grant Award, ICFO-Institute of Photonic Sciences, SPAIN

Member: Prof. Luis Martín Moreno, Universidad de Zaragoza, SPAIN

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