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We have measured the complex conductivity sigma of a Bi(2)Sr(2)CaCu(2)O(8+delta) thin film between 0.2 and 0.8 THz. We find sigma in the superconducting state to be well described as the sum of contributions from quasiparticles, condensate, and order parameter fluctuations which draw 30% of the spectral weight from the condensate. An analysis based on this decomposition yields a quasiparticle scattering rate on the order of k(B)T/Planck's over 2pi for temperatures below T(c). 相似文献
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Emission of symmetric flower-shaped light patterns from coherently locked hexagonal vertical-cavity semiconductor laser arrays is reported. The flower patterns preserve their shape while propagating in free space. The emission of these unique light distributions is explained as being due to the combined effects of thermal lensing and the loss patterns employed for array definition. A theoretical model for strongly coupled arrays matches the results. 相似文献
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Orenstein J 《Physical review letters》2011,107(6):067002
Rotation of the plane of polarization of reflected light (Kerr effect) is a direct manifestation of broken time-reversal symmetry and is generally associated with the appearance of a ferromagnetic moment. Here I identify magnetic structures that may arise within the unit cell of cuprate superconductors that generate polarization rotation despite the absence of a net moment. For these magnetic symmetries the Kerr effect is mediated by magnetoelectric coupling, which can arise when antiferromagnetic order breaks inversion symmetry. The structures identified are candidates for a time-reversal breaking phase in the pseudogap regime of the cuprates. 相似文献
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Indistinguishability of events in quantum mechanics is manifested by interference between their probability amplitudes. We report a unique kind of interference occurring between indistinguishable events of photon-pair emission, where each photon of the pair is emitted from a distinct true chaotic light source and has a different energy. The indistinguishability results in an interference which is observed as an ultrafast modulation of the second-order coherence function, measured on a femtosecond time scale by two-photon absorption in a semiconductor photomultiplier tube. 相似文献
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The fate of carriers excited in an amorphous semiconductor by a pulse of light is described. Two processes are discussed: thermalization of carriers within a distribution of localized states, and carrier recombination. 相似文献
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We present a concept of standing-wave optical frequency conversion in dispersive microcavities theoretically and experimentally, allowing efficient ultracompact nonlinear photonics. We developed a time-dependent model, incorporating the dispersion into the structure of the spatial cavity modes, where the conversion efficiency is enhanced by the optimization of a nonlinear cavity mode overlap. We designed and fabricated integrated double-resonance semiconductor microcavities for standing-wave second-harmonic generation. The measured efficiency exhibits a significant maximum near the cavity resonance owing to the intracavity power enhancement and the dispersion-induced wavelength detuning effect on the mode overlap, in good agreement with our theoretical predictions. 相似文献
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Coupling between whispering-gallery modes of concentric microcavity lasers was analyzed, and a closed-form three-dimensional vectorial solution for the coupled fields was obtained. Experiments performed with concentric gain-guided vertical cavity ring lasers resulted in regimes of resonant coupling in good agreement with the theory. 相似文献