Solid-state Microcavity Research Articles

Nonlinear optical response properties of a quantum dot embedded in a semiconductor microcavity: possible applications in quantum communication platforms

We theoretically investigate optical bistability, mechanically induced absorption (MIA) and Fano resonance of a hybrid system comprising of a single quantum dot (QD) embedded in a solid-state microcavity interacting with the quantized cavity mode and the deformation potential associated with the lattice vibration. We find that the bistability can be tuned by the QD-cavity mode coupling. We further show that the normalized power transmission displays anomalous dispersion indicating that the system can be used to generate slow light. We also demonstrate the possibility of using the system as all optomechanical Kerr switch.

Interactions and scattering of quantum vortices in a polariton fluid

Quantum vortices, the quantized version of classical vortices, play a prominent role in superfluid and superconductor phase transitions. However, their exploration at a particle level in open quantum systems has gained considerable attention only recently. Here we study vortex pair interactions in a resonant polariton fluid created in a solid-state microcavity. By tracking the vortices on picosecond time scales, we reveal the role of nonlinearity, as well as of density and phase gradients, in driving their rotational dynamics. Such effects are also responsible for the split of composite spin–vortex molecules into elementary half-vortices, when seeding opposite vorticity between the two spinorial components. Remarkably, we also observe that vortices placed in close proximity experience a pull–push scenario leading to unusual scattering-like events that can be described by a tunable effective potential. Understanding vortex interactions can be useful in quantum hydrodynamics and in the development of vortex-based lattices, gyroscopes, and logic devices.

DISTORTION TOLERANCE AGAINST GEOMETRY IMPERFECTIONS IN POLYMERIC MICROCAVITY DYE LASER

A polymeric solid-state microcavity dye laser of the size comparable to a lasing wavelength is modeled by means of the finite element method (FEM). Lasing modes are calculated taking into account the gain material properties, such as absorption, dispersion and fluorescence. Study of the microcavity tolerance against possible geometrical imperfections demonstrates good robustness of the chosen shape and stability of the operation under possible cavity distortions.

All amorphous SiC based luminescent microcavity

A series of amorphous silicon-carbide (a-SiC) films with various carbon content were deposited in plasma enhanced chemical vapor deposition system and their optical properties were systematically investigated. An intense and broad photoluminescence centered at 700 nm was observed at room temperature. By controlling the film thickness and composition of a-SiC films, all a-SiC film based optical microcavities were designed and prepared. The resonant enhancement of luminescence band at 645 nm was achieved and the luminescence band was significantly narrowed from 150 to 11 nm, which demonstrated the possibility to realize the solid state microcavity light emitting diodes.

Fabrication of three-dimensional microstructure in optical-gain medium using two-photon-induced photopolymerization technique

An approach using a laser-dye-doped dendrimer as a two-photon-induced photocurable resin was demonstrated for the fabrication of a three-dimensional microstructure. A dendrimer can encapsulate laser-dye and, as a result, increases its concentration up to 4 wt.% with limited energy transfer during the photopolymerization process. Confocal microscopic images showed a polymerized structure with a precise control of dimensions and spatial resolution within a submicrometer-scale. We fabricated a polymeric solid-state microcavity, which consisted of integrated strips arranged in a layer-by-layer structure. The microcavity had a periodic variation in the refractive index, which gave rise to Bragg reflection for laser feedback. Laser emission with a spectral linewidth of 0.15 nm was measured in the microcavity under optical excitation. This laser emission is attributed both to the distributed Bragg reflection and to the high gain of a polymeric medium containing a high concentration of laser-dye.

Two-photon-induced polymerization in a laser gain medium for optical microstructure

We have fabricated a polymeric solid-state microcavity in the laser gain media by a two-photon-induced polymerization technique. The photopolymerization resin contains conventional laser dye and dendrimer. A dendrimer can encapsulate the laser dye, and therefore increase its concentration up to 4 wt % with limited energy transfer during the photopolymerization process. The microcavity consisted of <0.4 μm linewidth polymerized strips arranged in layer-by-layer structure. The periodic variation in the refractive index gave rise to Bragg reflection. A laser emission was measured in the microcavity under optical excitation. The spectral linewidth was about 0.15 nm above the lasing threshold. The laser emission is attributed both to the distributed Bragg reflection and to the high gain of a polymeric medium containing laser dye with a high concentration.

Flat photonic bands in guided modes of textured metallic microcavities

A detailed experimental study of how wavelength-scale periodic texture modifies the dispersion of the guided modes of l/2 metal-clad microcavities is presented. We first examine the case of a solid-state microcavity textured with a single, periodic corrugation. We explore how the depth of the corrugation and the waveguide thickness affect the width of the band gap produced in the dispersion of the guided modes by Bragg scattering off the periodic structure. We demonstrate that the majority of the corrugation depths studied dramatically modify the dispersion of the lowest-order cavity mode to produce a series of substantially flat bands. From measurements of how the central frequency of the band gap varies with direction of propagation of the guided modes, we determine a suitable two-dimensional texture profile for the production of a complete band gap in all directions of propagation. We then experimentally examine band gaps produced in the guided modes of such a two-dimensionally textured microcavity and demonstrate the existence of a complete band gap for all directions of propagation of the lowest-order TE-polarized mode. We compare our experimental results with those from a theoretical model and find good agreement. Implications of these results for emissive microcavity devices such as light-emitting diodes are discussed.

Enhanced field ionization of excited atoms by inhibiting the spontaneous emission in a solid-state microcavity

Enhanced field ionization of excited atoms was observed in a solid-state microcavity (${\mathrm{C}\mathrm{a}\mathrm{S}:\mathrm{E}\mathrm{u}}^{2+}$ thin-film electroluminescent devices) by inhibiting their spontaneous emission. By increasing the lifetime of the excited ${\mathrm{Eu}}^{2+}$ atoms using the microcavity effect, the field-ionization rate was enhanced approximately three times over that without the microcavity. The characteristic temperature dependence of the enhanced field-ionization rate suggested the generation process was dissipative quantum tunneling induced by strong electron-phonon coupling between localized electrons in the excited ${\mathrm{Eu}}^{2+}$ atoms and the surrounding lattice vibrations of the CaS host in the solid-state microcavity.

Strain-tunable high- Q optical microsphere resonator

We demonstrate the tuning of high- Q optical whispering-gallery modes in a fused silica microsphere by applying mechanical strain. The measured total tunability is over 0.3 nm in the near-infrared band, with the undercoupled quality-factor being Q>1×10 8. The tunability of mode frequencies in this high- Q solid-state microcavity expands its applicability in quantum optics and photonics.