Bending light in a controllable way is desired in various applications such as beam steering, navigating and cloaking. Different from the conventional way to bend light by refractive index gradient, transformation optics or special beams through wavefront design such as Airy beams and surface plasmons, we proposed a mechanism to bend light via resonant adiabatic optical transition between Floqu...

Fano resonances - resonant scattering features with a characteristic asymmetric profile - have generated much interest, due to their extensive and valuable applications in chemical or biological sensors, new types of optical switches, lasers and nonlinear optics. They have been observed in a wide variety of resonant optical systems, including photonic crystals, metamaterials, metallic gratings ...

We propose a new accelerating concept, the chirpedpulse inverse free-electron laser (CPIFEL). We study the inverse free-electron laser (IFEL) accelerator both theoretically and computationally, and show that by using a femtosecond (fs), ultra-high-intensity drive laser pulse, the IFEL interaction bandwidth and accelerating gradient are increased, thus yielding large energy gains. Using a chirpe...

Wave transport in a media with a slow spatial gradient of its characteristics is found to exhibit a universal wave pattern ("gradient marker") in a vicinity of the maxima or minima of the gradient. The pattern is common for optics, quantum mechanics, and any other propagation governed by the same wave equation. Derived analytically, it has an elegantly simple yet nontrivial profile found in per...

A side-viewing, 2.3-mm diameter oblique incidence reflectometry endoscope has been designed to obtain optical property measurements of turbid samples. Light from a single-mode fiber is relayed obliquely onto the tissue with a gradient index lens-based distal optics assembly and the resulting diffuse reflectance profile is imaged and collected with a 30,000 element, 0.72 mm clear aperture fiber ...

Fluorescence enhanced tomography for molecular imaging requires low background for detection and accurate image reconstruction. In this contribution, we show that excitation light leakage is responsible for elevated background and can be minimized with the use of gradient index (GRIN) lenses when using fibre optics to collect propagated fluorescence light from tissue or other biological media. ...

The past few years have witnessed tremendous achievements of transformation optics applied to metallic plasmonic systems. Due to the poor tunability of metals, however, the ultimate control over surface plasmons remains a challenge. Here we propose a new type of graphene plasmonic (GP) metasurfaces by shaping the dielectrics underneath monolayer graphene into specific photonic crystals. The rad...

We report evidence in GaP and InP nanowires for a coherent modulation of the structure along the wire axis. By using electron diffraction, we have observed an additional series of diffraction peaks consistent with a quasiperiodic placement of twinning boundaries along the wire. This observation is indeed unexpected, as the vapor-liquid-solid growth conditions used to produce the nanowires were ...

PT -symmetric optics is an emerging field, with numerous applications in photonics. Here, we theoretically propose and study PT -symmetric architectures supporting novel beam-propagation controlled by appropriate manipulation of the system’s amplifying and dissipative elements. The base-platforms to observe these dynamics are binary photonic waveguide lattices consisting of dimmers, with amplif...

Reflection-refraction properties of photonic barriers, formed by dielectric gradient nanofilms, for inclined incidence of both S - and P -polarized electromagnetic waves are examined by means of exactly solvable models. We present generalized Fresnel formulas, describing the influence of the nonlocal dispersion on the reflectance and transmittance of single- and double-layer gradient photonic b...