@article{xiao_kim_zavada_2007, title={Imaging properties of a metallic photonic crystal}, volume={101}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.2737771}, DOI={10.1063/1.2737771}, abstractNote={Imaging effects in metallic photonic crystals (PCs) are examined theoretically based on the finite difference time-domain method. The analysis shows that, in metallic PC-based systems, far-field images do form at the opposite side of the PC “lens” and more importantly, follow the rule of geometric optics with respect to the changes in the source position as a direct proof of negative refraction. However, the comparison of ideal left-handed media with a metallic PC suggests that the focusing effect in the PC based system is different from that of the ideal left-handed media in many aspects, due to the inhomogeneous nature of the PC. Particularly, strong dependence on the individual geometry as well as the frequency in the PC-based system renders the effective index sensitive to the variations and potentially limits its application as a superlens.}, number={11}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Xiao, D. and Kim, K. W. and Zavada, J. M.}, year={2007}, month={Jun}, pages={113105} }
 @article{xiao_kim_lazzi_zavada_2006, title={Tunable waveguiding in electrically programmable VO2-based photonic crystals}, volume={99}, ISSN={["1089-7550"]}, DOI={10.1063/1.2200873}, abstractNote={The feasibility of electrically programmable waveguiding in a photonic crystal (PC) is explored based on the metal-insulator transition of vanadium dioxide (VO2). Unlike the ordinary PCs, wave propagation in the desired structure may be switched on/off or redirected by applying an electrical bias on the selective electrodes by taking advantage of the electrically induced VO2 phase transition and subsequent modulation of dielectric properties. The characteristics of the two-dimensional VO2-based PCs with line defects are analyzed using the iterative plane wave and finite difference time domain methods. Particularly, the influence of the Drude relaxation on waveguiding is examined as the high rate typical for metallic VO2 can lead to the signal loss. An optimized structure is proposed to minimize the loss and simplify the fabrication.}, number={11}, journal={JOURNAL OF APPLIED PHYSICS}, author={Xiao, D. and Kim, K. W. and Lazzi, G. and Zavada, J. M.}, year={2006}, month={Jun} }
 @article{xiao_kim_zavada_2005, title={Electrically programmable photonic crystal slab based on the metal-insulator transition in VO2}, volume={97}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.1898435}, DOI={10.1063/1.1898435}, abstractNote={The possibility of an electrically programmable photonic crystal is investigated theoretically based on the metal-insulator transition of vanadium dioxide (VO2). Recent experiments indicate that this phase transition of the first order can be controlled via external bias and results in significant changes in the electrical and optical properties of VO2. We propose a slab structure based on VO2 whose dielectric properties are modulated periodically in the in-plane direction by selectively inducing phase transition through a lithographically defined array of gate electrodes. A two-dimensional photonic band calculation predicts the presence of a band gap, clearly illustrating the feasibility of the proposed structure. The electrically controlled nature may enable the VO2- based structure to be programmable at a very high speed.}, number={10}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Xiao, D. and Kim, K. W. and Zavada, J. M.}, year={2005}, month={May}, pages={106102} }
 @article{xiao_kim_bedair_zavada_2004, title={Design of white light-emitting diodes using InGaN/AlInGaN quantum-well structures}, volume={84}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.1644920}, DOI={10.1063/1.1644920}, abstractNote={Based on the Rashba–Sheka–Pikus Hamiltonian in the vicinity of the Γ point, and taking into consideration spontaneous and piezoelectric polarization, the optical intensity of nitride-based quantum-well light-emitting diodes has been calculated. It is found that strain substantially alters the subband structure and thus the output intensity of these nitride-biased quantum-well light-emitting diodes. A design that uses AlInGaN as the quantum barrier is proposed to realize efficient red emission, which is hard to achieve if GaN is used as the barrier. In the proposed design, three different InGaN/AlInGaN quantum-well structures emit red, green, and blue light of similar intensity. Also, to achieve high efficiency, important factors related to the oscillator strength are discussed in detail.}, number={5}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Xiao, D. and Kim, K. W. and Bedair, S. M. and Zavada, J. M.}, year={2004}, month={Feb}, pages={672–674} }
 @article{xiao_kim_zavada_2004, title={Envelope-function analysis of wurtzite InGaN/GaN quantum well light emitting diodes}, volume={96}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.1755435}, DOI={10.1063/1.1755435}, abstractNote={Fundamental electrical and optical properties of strained wurtzite InGaN/GaN-based quantum-well light-emitting diodes are calculated based on the Rashba–Sheka–Pikus Hamiltonian in the vicinity of the Γ point. It is found that the strain and the strain-induced piezoelectric field significantly alter the subband structure and determines the output intensity of the nitride quantum well light emitting diodes. For the case with high In composition (≳0.2), the calculation also supports the possibility of strain relaxation in the quantum well. Coupled with an optimized set of parameters, our theoretical model provides an excellent agreement with the available experimental data over a wide range of In composition (0–0.5).}, number={1}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Xiao, D. and Kim, K. W. and Zavada, J. M.}, year={2004}, month={Jul}, pages={723–728} }