Kirill A. Atlasov

Wavelength and loss splitting in directly coupled photonic-crystal defect microcavities

Coupling between photonic-crystal defect microcavities is observed to result in a splitting not only of the mode wavelength but also of the modal loss. It is discussed that the characteristics of the loss splitting may have an important impact on the optical energy transfer between the coupled resonators. The loss splitting--given by the imaginary part of the coupling strength--is found to arise from the difference in diffractive out-of-plane radiation losses of the symmetric and the antisymmetric modes of the coupled system. An approach to control the splitting via coupling barrier engineering is presented.

Photonic-crystal microcavity laser with site-controlled quantum-wire active medium

Site-controlled quantum-wire photonic-crystal microcavity laser is experimentally demonstrated using optical pumping. The single-mode lasing and threshold are established based on the transient laser response, linewidth narrowing, and the details of the non-linear power input-output characteristics. Average-power threshold as low as approximately 240 nW (absorbed power) and spontaneous emission coupling coefficient beta approximately 0.3 are derived.

Large mode splitting and lasing in optimally coupled photonic-crystal microcavities

Coupling of L-type photonic-crystal (PhC) cavities in a geometry that follows inherent cavity field distribution is exploited for demonstrating large mode splitting of up to ~10-20 nm (~15-30 meV) near 1 µm wavelength. This is much larger than the disorder-induced cavity detuning for conventional PhC technology, which ensures reproducible coupling. Furthermore, a microlaser based on such optimally coupled PhC cavities and incorporating quantum wire gain medium is demonstrated, with potential applications in fast switching and modulation.

Effect of sidewall passivation in BCl3∕N2 inductively coupled plasma etching of two-dimensional GaAs photonic crystals

The effect of surface passivation in BCl3∕N2 inductively coupled plasma reactive-ion etching of GaAs-based photonic crystals (PhCs) was investigated. It is shown that sidewall passivation is crucial for achieving cylindrical, vertical PhC holes, where the exact shape of the hole is controlled via the N2 content in the plasma composition. The achieved quality of PhC membrane cavities was established by optical characterization of such cavities incorporating site-controlled quantum wires as integrated light source.

1D photonic band formation and photon localization in finite-size photonic-crystal waveguides

A transition from discrete optical modes to 1D photonic bands is experimentally observed and numerically studied in planar photonic-crystal (PhC) L(N) microcavities of length N. For increasing N the confined modes progressively acquire a well-defined momentum, eventually reconstructing the band dispersion of the corresponding waveguide. Furthermore, photon localization due to disorder is observed experimentally in the membrane PhCs using spatially resolved photoluminescence spectroscopy. Implications on single-photon sources and transfer lines based on quasi-1D PhC structures are discussed.

1D and 2D arrays of coupled photonic crystal cavities with a site-controlled quantum wire light source

We investigated experimentally 1D and 2D arrays of coupled L3 photonic crystal cavities. The optical modes of the coupled cavity arrays are fed by a site-controlled quantum wire light source. By performing photoluminescence measurements and relying on near-field calculation of the cavitiy modes, we evidence optical coupling between the cavities as well as supermode delocalization. In particular, for small cavity separations, fabrication induced disorder effects are shown to be negligible compared to optical coupling between cavities.

Observation of stimulated emission and lasing in quantum-wire photonic-crystal nanocavities

Low-threshold lasing is experimentally achieved for the first time in semiconductor photonic-crystal nanocavities embedding site-controlled quantum wires. The effect is established via direct observation of the stimulated emission in the time domain.

Polarization control of wafer-fused long-wavelength VCSELs using sub-wavelength shallow gratings

Polarization stable, wafer-fused 1310 nm VCSELs employing sub-wavelength shallow gratings on their top DBR and emitting 1.5 mW single mode output power in the 20degC-75degC temperature range are demonstrated.

Integration of site-controlled pyramidal quantum dots and photonic crystal membrane cavities

Deterministic integration of site-controlled InGaAs/GaAs quantum dots (QDs) with photonic crystal cavities is demonstrated. Fine adjustment of QD position (within ~10 nm) and emission energy (few meV) allows construction of coupled QD systems.

Phonon-mediated exciton-photon coupling in site-controlled quantum-dot-nanocavity systems

We show that far off-resonance exciton-photon coupling reported for self-assembled quantum dots in optical microcavities is not universal, and demonstrate that site-controlled dots exhibit clean phonon-mediated resonant coupling.