Summary thesis Ivan nikolaev

This thesis describes time- and angle-resolved experiments, in which effects of three-dimensional photonic crystals on spontaneous emission of embedded light sources (quantum dots and dye molecules) were studied.

Chapter 2 gives a detailed description of the theoretical basics of the interaction between light and matter including the process of spontaneous emission and propagation of light in photonic crystals.

Chapter 3 presents a discussion on experimentally realized photonic-bandgap structures, optical probes necessary for studying the interaction of light with real photonic crystals and light sources that can be used as internal fluorescent probes. The role of unavoidable structural disorder in light propagation through real photonic crystals is considered.

Chapter 4 describes the angle-resolved measurements of emission spectra from laser dyes and quantum dots in opal and inverse-opal photonic crystals. Pronounced directional dependencies of the emission spectra were observed. The measurements are quantitatively explained with a model that unifies diffuse light transport and photonic band structure.

Chapter 5 presents an experimental proof of strongly modified emission decay rates from CdSe quantum dots in titania inverse-opal photonic crystals. Both inhibition and enhancement of the emission decay rates are observed when the crystal lattice parameter was varied. The measured non-exponential decay curves were successfully described with a continuous distribution of decay rates.

In Chapter 6 the local density of optical states (LDOS) in the titania inverse opals is discussed. We found that the LDOS in the inverse opals strongly depends on the crystal lattice parameter as well as on the position and orientation of emitting dipoles. We identified conditions where the LDOS is strongly suppressed, strongly enhanced, and where sharp peaks (van Hove singularities) appear.

Chapter 7 presents a time-resolved study of spontaneous emission from opal photonic crystals doped with Rhodamine 6G dye, an emitter with a broad homogeneous linewidth. We have measured fluorescence lifetimes of the dye varying both optical frequency and crystal lattice parameter of the opals. We observed both increased and decreased lifetimes by changing the crystal lattice parameter. This modification is explained by the LDOS varying in the opals in bandwidths comparable to the homogeneous linewidth of the dye.