Here we discuss the experimental characterization of the spatial far-field profiles for the confined modes in a
photonic crystal cavity of the L3 type, finding a good agreement with FDTD simulations. We then link the
far-field profiles to relevant features of the cavity mode near-fields, using a simple Fabry-Perot resonator model.
Finally, we describe a technique for independent all-electrical control of the wavelength of quantum dots in
separated L3 cavities, coupled by a waveguide, by electrical isolation via proton implantation
We describe quantum information schemes involving photon polarization and the spin of a single electron trapped
in a self-assembled quantum dot. Such schemes are based on spin-selective reflection in the weak-coupling regime
of cavity quantum electrodynamics. We discuss their practical implementation in oxide-apertured micropillar
cavities. We introduce a technique, based on the creation of small surface defects by means of a focused intense
laser beam, to permanently tune the optical properties of the microcavity without damaging the cavity quality.
This technique allows low-temperature polarization-selective tuning of the frequencies of the cavity modes and
the quantum dot optical transitions.
We have measured the angle and wavelength dependent transmission of index matched metal hole arrays, and
of arrays with a dielectric pillar in each hole. Index matching enhances the transmission, but also broadens the
resonances due to an enhanced coupling between plasmon and radiation modes. Hole arrays that are covered
with glass or have a glass pillar in each hole are created using an imprinting technique. We observe additional
waveguide modes in the transmission spectra of these arrays and discuss the avoided crossing that we observe
for the hybrid structure with dielectric pillars in the holes.
We demonstrate and compare three different experimental techniques to characterize the quality of periodically poled
crystals. All techniques are based on the observation and analysis of Maker fringes in either spontaneous
parametric down-conversion (SPDC) or second harmonic generation (SHG). For perfectly-poled crystals these
Maker fringes are expected to have a sinc2-shape. We show how the observed deviations from this ideal shape
can be used to characterize the quality of the poling structure and analyze them with a new Fourier method,
which distinguished between variations in the poling composition and poling period.
We review a relatively simple model for VCSEL polarization noise, which is based on the adiabatic elimination of the carrier spin dynamics, and show how this 2-dimensional model can often be further simplified to a 1-dimensional (Kramers) model. Experimental verification for the validity of these models comes from a series of experiments on proton-implanted and etched-post VCSELs. We quantify the amount of linear and nonlinear birefringence and dichroism, we demonstrate a polarization-type of four-wave mixing, and discuss the correlated modal intensity fluctuations in the two polarization modes. Finally, we discuss the jump statistics of a VCSEL with stochastic polarization switches, and present a time-resolved observation of the polarization evolution during such a switch.
We present a detailed device characterization of a series of optically pumped VCSELs, emphasizing in particular a comparison with electrically pumped devices. We conclude that fundamental device parameters such as threshold pump power, input-output efficiency and polarization behavior do not depend on the pumping scheme.
Vertical-cavity surface-emitting lasers (VCSELs) are a new type of semiconductor laser with intriguing properties. As the small cavity ensures single longitudinal mode operation, the VCSEL mode structure is fully determined by the transverse spatial profile combined with the polarization behavior. After discussing some general ideas behind mode formation in VCSELs, we present a number of experiments performed to obtain the relevant numbers for practical AlGaAs-GaAs devices. These include measurements of: the (polarization-resolved) light output-versus-current characteristic, far-field patterns, the wavefront curvature inside a VCSEL, a spectral analysis of spontaneous emission below and above threshold, and a study of the influence of an axial magnetic field. This article contains a relatively large number of equations and experimental and literature values to make it more useful for later reference. Of course it is difficult to tell how specific some of these numbers are related to the particular planar VCSELs we have investigated.