Presentations

    Dirac-cone based negative/zero/positive refractive index metamaterials, at SPIE Photonics West: Photonic and Phononic Properties of Engineered Nanostructures IV (San Francisco, California), Thursday, February 6, 2014
    Based on accidental degeneracy, a Dirac-cone can be formed at the center of the Brillouin zone of a photonic crystal, which can be treated as a homogeneous bulk metamaterial in the vicinity of Dirac-point. In the vicinity below (above) the Dirac-point, the backward-wave (forward-wave) implies negative (positive) n_eff; at Dirac-point, k=0 induces zero n_eff. This negative/zero/positive refractive index shows low-loss and good impedance matching to free-space. According to this principle, we designed a Dirac-cone based metamaterial consisting of 2D square array of silicon pillars operating... Read more about Dirac-cone based negative/zero/positive refractive index metamaterials
    Nonlinear Phase-Matching in 2D Integrated Zero-Index Metamaterials, at MRS: Optical Metamaterials - From New Plasmonic Materials to Metasurface Devices (Boston, MA), Wednesday, December 2, 2015:
    Nonlinear optics play an important role in many applications in photonics and quantum optics, such as in frequency conversion, sensing, and entangled-photon generation. The strong field confinement obtained by the transition to an integrated platform has led to unprecedented nonlinear figures of merit and the miniaturization of nonlinear devices. However, phase-matching remains an essential component to nonlinear processes and represents a significant obstacle, with many different free-space and on-chip techniques being developed to circumvent its constraints. Recently, a 1-dimensional... Read more about Nonlinear Phase-Matching in 2D Integrated Zero-Index Metamaterials
    Zero-index waveguides for metasurface applications, at 2015 MRS Fall Meeting (Boston, Massachusetts), Wednesday, December 2, 2015:
    Metamaterials with a refractive index of zero have emerged as a new tool for phase control in nanophotonics. Waves propagate within such metamaterials with infinite phase velocity, resulting in uniform phase throughout. Recently two-dimensional zero-index metamaterials have been integrated with on-chip silicon photonics, allowing for phase-free propagation over large areas. However, zero-index modes are inherently lossy: since the momentum of the wave is zero, it lies above the light line, and therefore couples to waves in free space. In particular, momentum conservation implies that the... Read more about Zero-index waveguides for metasurface applications