Hybrid Microcavity Research Articles

High resolution pixel definition in hybrid microcavities

In this work, we demonstrate the realization of a multicolor organic microcavity built in a single step process by locally tuning the optical length of the cavity by means of a suitable pattern. A lithographic 3D hard pattern has been realized on the surface of the top mirror and then pressed over the bottom one, which was coated with a PMMA-rubrene blend. Because of the different height of the pattern, the optical length of the cavity is spatially modulated, while the physical length remains constant on the whole device. This allows to locally tune the single mode resonance with a high spatial resolution.

Polarization mixing in hybrid organic–inorganic microcavities

We use a microscopic theory to study hybrid organic–inorganic microcavities in the strong coupling regime. The optically resonant materials are an anisotropic crystalline organic mono-layer and a semiconductor quantum-well, which are coupled only via the cavity photons. The cavity eigenmodes are the hybrid Frenkel–Wannier–Mott exciton-polaritons. Using the quasi-mode approach, we calculate the hybrid cavity linear optical spectra, i.e. the transmission, reflection, and absorption spectra. In hybrid microcavities the anisotropic organic materials induce a mixing between the TE and TM cavity photon polarizations, and a mixing between the transverse and longitudinal heavy-hole (HH) Wannier–Mott excitons, which is in contrast to the case of ordinary semiconductor microcavities.

Room temperature polariton luminescence from a GaN∕AlGaN quantum well microcavity

The authors report on the demonstration of strong light-matter coupling at room temperature using a crack-free UV microcavity containing GaN∕AlGaN quantum wells (QWs). Lattice-matched AlInN∕AlGaN distributed Bragg reflectors (DBRs) with a maximum peak reflectivity of 99.5% and SiO2∕Si3N4 DBRs were used to form high finesse hybrid microcavities. State-of-the-art GaN∕Al0.2Ga0.8N QWs emitting at 3.62eV with a linewidth of 45meV at 300K were inserted in these structures. For a 3λ∕2 microcavity containing six QWs, the interaction between cavity photons and QW excitons is sufficiently large to reach the strong coupling regime. A polariton luminescence is observed with a vacuum field Rabi splitting of 30meV at 300K.

High Q-factor colloidal nanocrystal-based vertical microcavity by hot embossing technology

We report on the fabrication and optical characterization of vertical hybrid microcavities in which a layer of colloidal nanocrystals dispersed in an organic matrix is embedded between two inorganic mirrors. The devices are fabricated by a technique based on the unconventional use of the hot embossing technology, which allows a very fine control of the cavity length. The technique exploits a λ-thick microstructured dielectric top mirror pressed onto the bottom one, previously coated with the active layer, to sandwich the cavity and precisely control its thickness. Room-temperature photoluminescence measurements show a Q factor as high as 146 for our devices.

AlGaN‐based Bragg mirrors and hybrid microcavities for the ultra‐violet spectral region

Epitaxially grown AlGaN-AlGaN Bragg mirrors and AlInGaN-AlGaN quantum well cavity regions designed for operation in the ultra-violet spectral region are reported. Full cavities are completed by deposition of dielectric top mirrors. We obtain high AlGaN-AlGaN mirror reflectivities of up to 94%, and cavity Q-values close to 100. We also demonstrate the successful growth of 2.5nm linewidth quantum wells on 25 layer-repeat Bragg mirrors. These results are promising first steps towards the realisation of AlGaN-based microcavity polariton devices. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Rate and efficiency of spontaneous emission in metal-clad microcavities

In this article, we report experimental results on the control of spontaneous emission from sources embedded within metal-clad microcavities. The microcavity samples consist of an Eu3+ doped emissive monolayer embedded with a planar dielectric slab, bounded by a silver film on each side. We investigate the effect of both the cavity thickness and the location of the emissive monolayer within the cavity on the spontaneous emission rate of the emitters, observing both enhancement and inhibition. By varying the thickness of one of the silver films we also investigate the role of the reflectivity of the mirrors of the cavity on the control of spontaneous emission. In addition to the emission rate, results are presented on the spatial distribution of the emitted radiation. We find good agreement between our experimental results and those predicted by a classical theory over a large range microcavity structures. This agreement allows us to assess the contribution of the decay mediated by the electromagnetic modes of the cavity and the intrinsic nonradiative decay to the spontaneous emission rate. We then compare the ability of metal-clad and hybrid (one metal mirror and one distributed Bragg reflector) microcavity designs to optimize the efficiency of radiative emission. We show that enhancements, due to the increased confinement of the electromagnetic modes supported by the metal-clad microcavities, can be sufficient to overcome the loss associated with the absorption in the metal layers. We discuss the implication these results may have for device design.