1,796 research outputs found
Quantum theory of photonic crystal polaritons
We formulate a full quantum mechanical theory of the interaction between
electromagnetic modes in photonic crystal slabs and quantum well excitons
embedded in the photonic structure. We apply the formalism to a high index
dielectric layer with a periodic patterning suspended in air. The strong
coupling between electromagnetic modes lying above the cladding light line and
exciton center of mass eigenfunctions manifests itself with the typical
anticrossing behavior. The resulting band dispersion corresponds to the
quasi-particles coming from the mixing of electromagnetic and material
excitations, which we call photonic crystal polaritons. We compare the results
obtained by using the quantum theory to variable angle reflectance spectra
coming from a scattering matrix approach, and we find very good quantitative
agreement.Comment: Proceedings of the "8th Conference on Optics of Excitons in Confined
Systems" (OECS-8), 15-17 September 2003, Lecce (Italy
Band structure and optical properties of opal photonic crystals
A theoretical approach for the interpretation of reflectance spectra of opal
photonic crystals with fcc structure and (111) surface orientation is
presented. It is based on the calculation of photonic bands and density of
states corresponding to a specified angle of incidence in air. The results
yield a clear distinction between diffraction in the direction of light
propagation by (111) family planes (leading to the formation of a stop band)
and diffraction in other directions by higher-order planes (corresponding to
the excitation of photonic modes in the crystal). Reflectance measurements on
artificial opals made of self-assembled polystyrene spheres are analyzed
according to the theoretical scheme and give evidence of diffraction by
higher-order crystalline planes in the photonic structure.Comment: to appear in PR
Pengaruh Spread Tingkat Suku Bunga dan Rasio Keuangan terhadap Penyaluran Kredit UMKM pada Bank Umum di Indonesia
Penelitian ini dilakukan untuk menguji pengaruh Spread tingkat suku bunga bank, Capital Adequacy Ratio (CAR), Loan to Deposit Ratio (LDR), dan Non Performing Loan (NPL) terhadap Penyaluran Kredit Usaha Mikro Kecil Menengah baik secara simultan maupun parsial. Objek penelitian yaitu pada Bank Umum yang terdaftar di Bank Indonesia untuk periode 2008–2011. Teknik sampling yang digunakan adalah purposive sampling sehingga dari 109 Perusahaan diperoleh sebanyak 73 Perusahaan yang akan dijadikan sebagai objek penelitian. Teknik analisa data yang digunakan adalah analisis regresi berganda. Berdasarkan hasil pengujian data diketahui bahwa secara simultan dan parsial, spread, CAR, LDR dan NPL berpengaruh terhadap penyaluran kredit UMKM pada bank umum yang terdaftar di Bursa Efek Indonesia untuk periode 2008-201
Pengaruh Reaksi Pasar terhadap Harga Saham Perusahaan yang Terdaftar di Bursa Efek Indonesia
Penelitian ini dilakukan untuk mengetahui dan menganalisa pengaruh dari Volume Perdagangan Saham dan abnormal return terhadap harga saham Perusahaan yang terdaftar di Bursa Efek Indonesia untuk periode 2008-2012. Sampel dalam penelitian ini berjumlah 90 Perusahaan yang terdaftar di Bursa Efek Indonesia. Metode analisis data yang digunakan adalah analisis regresi linear berganda. Berdasarkan hasil penelitian, diketahui bahwa abnormal return dan Volume Perdagangan Saham secara simultan mempengaruhi harga saham. Namun secara parsial, Volume Perdagangan Saham tidak berpengaruh signifikan terhadap harga saham, sedangkan variabel abnormal return yang dihitung dengan menggunakan mean adjusted model, market adjusted model, dan market model berpengaruh signifikan terhadap harga saham Perusahaan yang terdaftar di Bursa Efek Indonesia periode 2008-2012
Exciton polaritons in two-dimensional photonic crystals
Experimental evidence of strong coupling between excitons confined in a
quantum well and the photonic modes of a two-dimensional dielectric lattice is
reported. Both resonant scattering and photoluminescence spectra at low
temperature show the anticrossing of the polariton branches, fingerprint of
strong coupling regime. The experiments are successfully interpreted in terms
of a quantum theory of exciton-photon coupling in the investigated structure.
These results show that the polariton dispersion can be tailored by properly
varying the photonic crystal lattice parameter, which opens the possibility to
obtain the generation of entangled photon pairs through polariton stimulated
scattering.Comment: 5 pages, 4 figure
Polariton Dispersion Law in Periodic Bragg and Near-Bragg Multiple Quantum Well Structures
The structure of polariton spectrum is analyzed for periodic multiple quantum
well structures with periods at or close to Bragg resonance condition at the
wavelength of the exciton resonance. The results obtained used to discuss
recent reflection and luminescent experiments by M. H\"{u}bner et al [Phys.
Rev. Lett. {\bf 83}, 2841 (1999)] carried out with long multiple quantum well
structures. It is argued that the discussion of quantum well structures with
large number of wells is more appropriate in terms of normal modes of infinite
periodic structures rather then in terms of super- and sub- radiant modes.Comment: replaced with a new version, an error in one of the equations is
correcte
Analisis Faktor-Faktor yang Mempengaruhi Persistensi Laba pada Perusahaan Manufaktur di Bursa Efek Indonesia
Penelitian ini bertujuan untuk menguji dan menganalisis pengaruh aliran kas operasi, perbedaan antara laba akuntansi dengan laba fiskal dan tingkat hutang secara simultan maupun parsial terhadap persistensi laba pada Perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia untuk periode 2009 sampai 2011. Metode analisis data yang digunakan adalah analisis regresi linear berganda. Populasi dalam penelitian ini adalah semua Perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia periode 2009 sampai 2011. Dengan menggunakan teknik purposive sampling diperoleh 58 Perusahaan yang akan dijadikan sebagai sampel penelitian. Hasil penelitian menunjukkan bahwa secara simultan, aliran kas operasi, perbedaan antara laba akuntansi dengan laba fiskal dan tingkat hutang berpengaruh signifikan terhadap persistensi laba pada Perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia periode 2009 sampai 2011. Namun secara parsial, hanya aliran kas operasi berpengaruh positif dan signifikan terhadap persistensi laba, sedangkan perbedaaan antara laba akuntansi dengan laba fiskal dan tingkat hutang tidak berpengaruh signifikan terhadap persistensi laba pada Perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia (BEI) periode 2009-2011
Profile alterations of a symmetrical light pulse coming through a quantum well
The theory of a response of a two-energy-level system, irradiated by
symmetrical light pulses, has been developed.(Suchlike electronic system
approximates under the definite conditions a single ideal quantum well (QW) in
a strong magnetic field {\bf H}, directed perpendicularly to the QW's plane, or
in magnetic field absence.) The general formulae for the time-dependence of
non-dimensional reflection {\cal R}(t), absorption {\cal A}(t) and transmission
{\cal T}(t) of a symmetrical light pulse have been obtained. It has been shown
that the singularities of three types exist on the dependencies {\cal R}(t),
{\cal A}(t), {\cal T}(t). The oscillating time dependence of {\cal R}(t), {\cal
A}(t), {\cal T}(t) on the detuning frequency \Delta\omega=\omega_l-\omega_0
takes place. The oscillations are more easily observable when
\Delta\omega\simeq\gamma_l. The positions of the total absorption, reflection
and transparency singularities are examined when the frequency \omega_l is
detuned.Comment: 9 pages, 13 figures with caption
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