Quantum wires in multidimensional microcavities: Effects of photon dimensionality on emission properties

Seeded self-ordered, strained, 10-nm-size ${\mathrm{In}}_{0.15}{\mathrm{Ga}}_{0.85}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ V-groove quantum wires (QWR’s) have been incorporated into multidimensional, high finesse $\left(Q\sim 5000\right),$ micron-size ${\mathrm{A}\mathrm{l}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.07}{\mathrm{Ga}}_{0.93}\mathrm{As}$ photon-well, photon-wire (PWR), and photon-dot (PD) Bragg-air microcavities. The impact of the photon dimensionality on the QWR spontaneous emission is systematically elucidated in the spectral, spatial, temporal, and polarization domains using different microphotoluminescence techniques. Larger effects are demonstrated for resonant cavities confining in multiple dimensions and of smaller sizes. We observe increasingly rich structuring of the emission spectra and patterns for decreasing cavity dimensionality, leading to a series of sharp (0.28 meV) lines with enhanced intensities $(\times 50)$ at specific directions in fully confined PD’s. Photon lateral confinement in PWR’s and PD’s is necessary to evidence cavity-induced polarization effects and a spontaneous emission rate enhancement by a Purcell factor of $\times 1.7,$ limited by the QWR inhomogeneous broadening. The results are interpreted in terms of the redistribution of the QWR emission into confinement-induced resonances in the photon mode distribution in the different cavities. In particular, systematic wave-vector quantization in the directions of photon confinement, and dispersive behavior in the free propagation directions are evidenced in close agreement with model calculations.