Browsing by Author "Chen, Minfeng"

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Finite-difference time-domain analysis for the dynamics and diffraction of exciton-polaritons
(2015-10-01)
Chen, Minfeng
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Chang, Yia-Chung
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Hsieh, Wen-Feng
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光電工程學系
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Department of Photonics
We adopted a finite-difference time-domain (FDTD) scheme to simulate the dynamics and diffraction of exciton-polaritons, governed by the coupling of polarization waves with electromagnetic waves. The polarization wave, an approximate solution to the Schrodinger\'s equation at low frequencies, essentially captures the exciton behavior. Numerical stability of the scheme is analyzed and simple examples are provided to prove its validity. The system considered is both temporally and spatially dispersive, for which the FDTD analysis has attracted less attention in the literature. Here, we demonstrate that the FDTD scheme could be useful for studying the optical response of the exciton-polariton and its dynamics. The diffraction of a polariton wave from a polaritonic grating is also considered, and many sharp resonances are found, which manifest the interference effect of polariton waves. This illustrates that the measurement of transmittance or reflectance near polariton resonance can reveal subwave-length features in semiconductors, which are sensitive to polariton scattering. (C) 2015 Optical Society of America
Resonant modes of 12-fold symmetric defect free photonic quasicrystal
(2014-01-27)
Chen, Minfeng
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Li, Yun-Jing
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Cheng, Yuh-Jen
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Chang, Yai-Chung
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Chang, Chun-Yen
This work investigates the resonant modes of a 12-fold symmetric defect free photonic quasicrystal (PQC) nanorod array using finite difference time domain (FDTD) simulation. Localized modes can exist in PQC without introducing defects due to the lack of translational symmetry. The resonant modes of the unit cell PQC and the one time expanded PQC from unit cell are systematically examined. The resonant spectrum is that of a single rod modified by the interaction among PQC nanorods. The mode confinement is contributed by guided resonance and destructive interference scattering. The self-scaling similarity of resonant spectrum and mode profile are also investigated. (C) 2014 Optical Society of America