Dielectric Functions of CdSe and ZnSe Obtained by Using Vacuum Ultra-Violet Spectroscopic Ellipsometry

Kim, T. J.; Lee, S. Y.; Choi, A. J.; Kim, Y. D.

doi:10.3938/jkps.50.806

Cited by 8 publications

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“…ductors with band structure similar to GaAs. The electronic band-gaps of CdTe and Cd 0.6 Mg 0.4 Te are 1.475 eV and 2.28 eV, respectively [57,58] (from linear interpolation between the band gaps of CdTe and MgTe, the latter being 3.49 eV). The cladding rods without QWs are also made of Cd 0.6 Mg 0.4 Te.…”

Section: Figmentioning

confidence: 99%

Photonic Crystal Architecture for Room-Temperature Equilibrium Bose-Einstein Condensation of Exciton Polaritons

Jiang

John

2014

Phys. Rev. X

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We describe photonic crystal microcavities with very strong light-matter interaction to realize roomtemperature, equilibrium, exciton-polariton Bose-Einstein condensation (BEC). This goal is achieved through a careful balance between strong light trapping in a photonic band gap (PBG) and large exciton density enabled by a multiple quantum-well (QW) structure with a moderate dielectric constant. This approach enables the formation of a long-lived, dense 10 − μm − 1 − cm-scale cloud of exciton polaritons with vacuum Rabi splitting that is roughly 7% of the bare exciton-recombination energy. We introduce a woodpile photonic crystal made of Cd 0.6 Mg 0.4 Te with a 3D PBG of 9.2% (gap-to-central-frequency ratio) that strongly focuses a planar guided optical field on CdTe QWs in the cavity. For 3-nm QWs with 5-nm barrier width, the exciton-photon coupling can be as large as ℏΩ ¼ 55 meV (i.e., a vacuum Rabi splitting of 2ℏΩ ¼ 110 meV). The exciton-recombination energy of 1.65 eV corresponds to an optical wavelength of 750 nm. For N ¼ 106 QWs embedded in the cavity, the collective exciton-photon coupling per QW (ℏΩ= ffiffiffiffi N p ¼ 5.4 meV) is much larger than the state-of-the-art value of 3.3 meV, for the CdTe Fabry-Pérot microcavity. The maximum BEC temperature is limited by the depth of the dispersion minimum for the lower polariton branch, over which the polariton has a small effective mass of approximately 10 −5 m 0 , where m 0 is the electron mass in vacuum. By detuning the bare exciton-recombination energy above the planar guided optical mode, a larger dispersion depth is achieved, enabling room-temperature BEC. The BEC transition temperature ranges as high as 500 K when the polariton density per QW is increased to ð11a B Þ −2 , where a B ≃ 3.5 nm is the exciton Bohr radius and the exciton-cavity detuning is increased to 30 meV. A high-quality PBG can suppress exciton radiative decay and enhance the polariton lifetime to beyond 150 ps at room temperature, sufficient for thermal equilibrium BEC.

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Section: Figmentioning

confidence: 99%