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We introduce a synthetic frequency dimension in a one dimensional array of ring resonator system and generalize the concept of photonic gauge potential. A topologically protected edge state is created in the synthetic space.
Weyl point is a topological singular point in the momentum space. There are two types of Weyl points, type-I and type-II, both are topologically nontrivial but exhibit very different physical properties. For instance, the density of state is zero at a type-I Weyl point; while that of type-II Weyl point is rather large just like the hyperbolic metamaterials. Up to now, there has not been any exploration...
Surface plasmons are electromagnetic waves that propagate along the interface of a metal and a dielectric. In a surface plasmon light interacts with the free electrons of the metal which oscillate collectively in response to the applied field. Recently, nanometer-scale metallic devices have shown the potential to manipulate light at the subwavelength scale using surface plasmons. This could...
In the first part of this chapter, a theoretical overview is presented on the different approaches to the use of dynamic tuning for coherent optical pulse stopping and storage in coupled resonator systems, which are amenable to fabrication in on-chip devices such as photonic crystals. The use of such dynamic tuning overcomes the delay-bandwidth constraint of slow-light structures. The second part...
We discuss some of our recent works in understanding optical reciprocity without the use of magneto-optics. A key objective for optical non-reciprocal device is to provide optical isolation. We show that a large class of nonlinear optical isolators in fact is constraint by a dynamic reciprocity, and therefore cannot provide complete optical isolation. We also discuss topological effects in dynamic-modulation-induced...
We propose a waveguiding mechanism based on the effective gauge potential for photons, where the core and cladding regions have the same dispersion relation but are subject to different gauge potentials. This can be realized in a dynamically modulated resonator lattice, and provides a dynamically reconfigurable mechanism for generating a one-way waveguide.
We introduce general principles for maximally violating detailed balance in thermal radiation. We validate these principles by direct calculations, based on fluctuational electrodynamics, on thermal emitters constructed from magneto-optical photonic crystals.
We present the first experimental demonstration near-field radiative heat transfer using silicon carbide. We achieve a 11 Ox near-field enhancement, relative to the far-field limit, of the radiative heat transfer between integrated nanostructures.
Antireflection can be achieved using optical resonances. We show theoretically that complete resonant antireflection is possible if the resonances radiate in a balanced manner and the periodicity of the structure is subwavelength for normal incidence.
Antireflection coatings are necessary components in solar cells. It has recently been experimentally demonstrated that a periodic array of resonant subwavelength objects placed at an air-dielectric interface can significantly reduce reflection. We introduce the theoretical condition for complete reflection cancellation in this resonant antireflection scheme. First, the periodicity of the array needs...
Optimizing contrast enhancement in optical coherence tomography (OCT) is essential for producing specific image signals and realizing its potential use in various biomedical imaging fields besides ophthalmology and cardiology. Using nanoparticles as selective signal nanoamplifiers will be helpful to highlight the lesion sites and identify cancerous changes that are difficult to diagnose currently...
We elucidate the physics of optical impedance transformation and use this concept to design nanophotonic structures that provide broadband and omnidirectional improvement of transmission in transparent electrodes without compromising their electrical performances.
We observe an effective magnetic field for photons using an on-chip silicon-based Ramsey-type interferometer. This interferometer generates a direction-dependent phase which corresponds to a magnetic field of 0.2 Gauss in an Aharonov-Bohm configuration for electrons.
We demonstrate near-field radiative heat transfer between nanostructures and show that it dominates over other on-chip conduction channels. The measured heat transfer behavior matches the predictions of boundary element method simulations for parallel nanobeams.
We design a novel core-shell nanocone structure that allows full absorption of sunlight in an iron oxide photoanode. The photocurrent approaches 12.5mA/cm2 within an iron oxide thickness of 20nm, verified by full-field electromagnetic simulation.
We report the first demonstration of PT-symmetry and its breaking in a system of two directly-coupled on-chip whispering-gallery-mode microresonators[1]. We observed strong nonreciprocity due to strong-field localization and enhanced nonlinearity in the broken PT-symmetry phase.
We introduce a general approach to radiatively lower the temperature of a structure, while preserving its color under sunlight. The cooling persists in the presence of considerable non-radiative heat exchange, and for different solar absorptances.
We demonstrate ideal waveguide lenses with very large number of waveguides and with complete power concentration in a single waveguide. We also show for the first time an ideal waveguide lens structure.
In contrast to a conventional symmetric Lorentzian resonance, Fano resonance is predominantly used to describe asymmetric-shaped resonances, which arise from the constructive and destructive interference of discrete resonance states with broadband continuum states. This phenomenon and the underlying mechanisms, being common and ubiquitous in many realms of physical sciences, can be found in a wide...
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