The study of the behavior of exciton and photon within semiconductor microcavity under hydrostatic pressure

We studied, for the first time, the strong coupling between exciton and cavity mode within semiconductor microcavity under hydrostatic pressure, and measured the Rabi splitting. The strong coupling between exciton and cavity mode, and so Rabi splitting appear clearly as the applied pressure reaches 0.37-0.41 GPa. The experiment result shows that hydrostatic pressure not only can tune the coupling between exciton and cavity mode effectively, but also can keep exciton property almost unchanged during the whole tuning procedure in contrast to other tuning method (temperature field et al). Our result agrees with the related theory very well. The Rabi splitting, extracted from fitting the measured mode-energy vs pressure curves with correspanding theoretical model, is equal to 6 meV.

Coupling between cavity mode and heavy-hole exciton and light-hole exciton in semiconductor microcavity

The reflectivity spectra at different incident angles of semiconductor microcavity having heavy-hole exciton and light-hole exciton are calculated ly transfer matrix method using the linear dispersion model. Meanwhile we calculate the energy of three cavity polaritons at different incident angles formed by the coupling between cavity mode and the two exciton modes using the three harmonic oscillators coupling model, and the weights of cavity mode and the two exciton modes in the three cavity polaritons. The results indicate that there is obvious anticross between the high energy cavity polariton and the two low energy cavity polaritons with increasing incident angles, and the weights of three modes(cavity mode, heavy-hole exciton mode and light-hole exciton mode) in the three cavity polaritons increase or decrease.

Tuning of exciton-photon coupling in a planar semiconductor microcavity by applying hydrostatic pressure

By means of hydrostatic pressure tuning, we have observed the strong-coupling exciton-polariton mode in a planar microcavity with an InGaAs/GaAs quantum well embedded in it, over a pressure range from 0.37 to 0.41 GPa. The experimental data can be fitted very well to a corresponding theoretical formula with a unique value of the vacuum Rabi splitting equal to 6.0 meV. A comparison between pressure tuning and other tuning methods is made as regards to what extent the intrinsic features of the exciton and cavity will be influenced during the tuning procedure.

Design of quantum cascade microcavity lasers based on Q factor versus etching depth

The choice of the etching depth for semiconductor microcavities is a compromise between a high Q factor and a difficult technique in a practical fabricating process. In this paper, the influences of the etching depth on mode Q factors for mid-infrared quantum cascade microcylinder and microsquare lasers around 4.8 and 7.8 mu m are simulated by three-dimensional (3D) finite-difference time-domain (FDTD) techniques. For the microcylinder and the microsquare resonators, the mode Q factors of the whispering-gallery modes (WGMs) increase exponentially and linearly with the increase in the etching depth, respectively Furthermore, the mode Q factors of some higher order transverse WGMs may be larger than that of the fundamental transverse WGM in 3D microsquares. Based on the field distribution of the vertical multilayer slab waveguide and the mode Q factors versus the etching depth, the necessary etching depth is chosen at the position where the field amplitude is 1% of the peak value of the slab waveguide. In addition, the influences of sidewall roughness on the mode Q factors are simulated for microsquare resonators by 2D FDTD simulation. (C) 2009 Optical Society of America

Tunable giant Faraday rotation of exciton in semiconductor quantum wells embedded in a microcavity

The Faraday rotation of an exciton in a GaAs quantum well (QW) embedded in a microcavity is investigated theoretically. The authors find that the Faraday rotation is enhanced remarkably by the microcavity, with a magnitude about two orders of magnitude larger than that of a single QW without microcavity. The Faraday rotation can be tuned by changing the incident angle of the pump and probe lights, or by varying the temperature or an external electric field. With an appropriate detuning between the cavity mode of the pump and probe lights, the Faraday rotation spectrum displays a strongly asymmetric line shape, which can easily be detected experimentally.

Lasing of CdSSe quantum dots in glass spherical microcavity

Glass spherical microcavities containing CdSSe semiconductor quantum dots (QDs) of a few microns in diameter are fabricated using a physical method. When a single glass microspherical cavity is excited by a laser beam at room temperature, very strong and sharp whispering gallery modes are shown on the background of PL spectra of CdSSe QDs, which confirms that coupling between the optical emission of embedded QDs and spherical cavity modes is realized. For a glass microsphere only 4.6 mum in diameter, it was found that the energy separation is nearly up to 26 nm both for TE and TM modes. With the increasing excitation intensity, the excitation intensity dependence of the emission intensity is not linear in the double-logarithmic scale. Above the threshold value, the linewidths of resonance modes become narrower. The lasing behavior is achieved at relatively low excitation intensity at room temperature. High optical stability and low threshold value make this optical system promising in visible microlaser applications. (C) 2002 Elsevier Science B.V. All rights reserved.

Mode splitting in photoluminescence spectra of a quantum-dot-embedded microcavity

A microcavity structure, containing self-assembled InGaAs quantum dots, is studied by angle-resolved photoluminescence (PL) spectroscopy. A doublet with the splitting energy of 0.5-1.5 nm appears when the detection angle is larger than 35degrees. This doublet is identified as mode splitting (not the Rabi splitting) by polarization measurements. We find that it is the considerable deviation of the cavity-mode frequency from the central frequency of the stop band that makes the TE and TM cavity modes split more discernibly. The inhomogeneous broadening of quantum dots gives the TE and TM cavity modes a chance to show up simultaneously in the PL spectra. (C) 2003 American Institute of Physics.

Lasing of CdSexS1-x quantum dots in a glass spherical microcavity

A glass spherical microcavity only a few microns in diameter embedded with CdSexS1-x quantum dots (QDs) was fabricated using a physical method; it exhibited good optical stability under continuous-wave laser excitation with high power. We investigated the excitation power dependences of the emission intensity and the linewidth of both transverse electric and transverse magnetic resonance peaks of whispering gallery modes. Stimulated emission behaviour of multi-frequency modes is observed at room temperature. The low threshold value and large mode separation makes QD-containing microspheres promising for visible microlaser applications.

In-plane propagation of cavity polaritons in a quantum semiconductor microcavity

Considering that the coupling among the heavy-hole exciton, light-hole exciton and the cavity photon can form bipolaritons in a quantum semiconductor microcavity, we calculate the group velocities of the cavity polaritons at different incident angles using the coupling model of three harmonic oscillators. The result indicates that the group velocities of the low and middle branches of the cavity polaritons have extrema, but the group velocities of the high branch increase with the increasing incident angle.

Photoluminescence behavior of quantum dots in spherical glass microcavity

Micrometer-sized spherical glass microspheres were fabricated. CdSeS semiconductor nanometer clusters were incorporated into spherical microcavities. When a single microsphere was excited by a laser beam, the whispering gallery mode resonance of the photoluminescence of CdSeS quantum dots in the spherical microcavities was realized by the multiple total internal reflections at the spherical interface. The coupling of restricted electronic and photonic states was realized.

Photoluminescence study of CdSexS1-x quantum dots in a glass spherical microcavity

The photoluminescence (PL) of CdSexS1-x semiconductor quantum dots (QDs) in a glass spherical microcavity is investigated. The CdSexS1-x semiconductor clusters embedded in a glass matrix are fabricated by using the heat treatment method. Periodical structures consisting of sharp spectral lines are observed in the PL spectra of CdSexS1-x QDs, which can be well explained by the coupling with the whispering gallery modes of the spherical microcavity based on Mie scattering theory.

Exciton energy of the InAs/GaAs self-assembled quantum dot in a semiconductor microcavity

We report on the theoretical study of the interaction of the quantum dot (QD) exciton with the photon waveguide models in a semiconductor microcavity. The InAs/GaAs self-assembled QD exciton energies are calculated in a microcavity. The calculated results reveal that the electromagnetic field reduces the exciton energies in a semiconductor microcavity. The effect of the electromagnetic field decreases as the radius of the QD increases. Our calculated results are useful for designing and fabricating photoelectron devices.

Quantum dots in glass spherical microcavity

Glass spherical microcavities containing CdSexS1-x semiconductor quantum dots (QDs) are fabricated. The coupling between the optical emission of embedded CdSexS1-x QDs and spherical cavity modes is realized. When the luminescence of QDs is excited by a laser beam, the strong whispering gallery mode resonance with high Q factors is achieved in the photoluminescence spectra. (C) 2001 American Institute of Physics.

Dynamics of Cavity Polaritons in a GaAs Quantum-well Semiconductor Microcavity

To provide the dynamics of cavity polariton in semiconductor microcavity containing GaAs quantum-well, the dispersions of the three cavity polaritons have been given by the model of three coupled oscillators, meanwhile the linewidths, group velocities and the mass of the three cavity polaritons have been demonstrated. The results indicated that because of the weight occupied by the photon, heavy hole exciton and light hole extiton in the three cavity ploariton the cavity polaritons exhibited different dynamic behaviors.

Lasing of CdSSe quantum dots in glass spherical microcavity

Glass spherical microcavities containing CdSSe semiconductor quantum dots (QDs) of a few microns in diameter are fabricated using a physical method. When a single glass microspherical cavity is excited by a laser beam at room temperature, very strong and sharp whispering gallery modes are shown on the background of PL spectra of CdSSe QDs, which confirms that coupling between the optical emission of embedded QDs and spherical cavity modes is realized. For a glass microsphere only 4.6 mum in diameter, it was found that the energy separation is nearly up to 26 nm both for TE and TM modes. With the increasing excitation intensity, the excitation intensity dependence of the emission intensity is not linear in the double-logarithmic scale. Above the threshold value, the linewidths of resonance modes become narrower. The lasing behavior is achieved at relatively low excitation intensity at room temperature. High optical stability and low threshold value make this optical system promising in visible microlaser applications. (C) 2002 Elsevier Science B.V. All rights reserved.