Free controls of optic/acoustic waves for bending, focusing or steering the energy of wavefronts are highly desirable in many practical scenarios. However, the dispersive nature of the existing metamaterials/metasurfaces for wavefront manipulation necessarily results in limited bandwidth. Here, we propose the concept of dispersionless wavefront manipulation and report a theoretical, numerical a...

Adaptive optics in astronomical and other imaging systems allows compensation of aberrations introduced by random variations of the refractive index in the imaging path. I propose what I believe is a new type of adaptive optics system that dispenses with the hardware lenslet arrays and deformable mirrors of conventional systems. Theoretical and experimental studies show that wavefront sensing a...

We propose a design for broadband waveguide mode conversion based on gradient index metamaterials (GIMs). Numerical simulations demonstrate that the zeroth order of transverse magnetic mode or the first order of transverse electric mode (TM0/TE1) can be converted into the first order of transverse magnetic mode or the second order of transverse electric mode (TM1/TE2) for a broadband of frequen...

the degree of aromaticity of mono-substituted derivatives of benzene has beeninvestigated using a new index based on electric field gradient index, by using two mechanicalquantum methods with gaussian 03. two different basis sets have applied to study and theresults compared. this strategy has demonstrated that, due to violation of symmetry in have pisystems,how the degree of aromaticity can ha...

Above: Opal detail. Below: The eye of the " silver-spotted skipper " butterfl y (Epargyreus clarus), which has negative-refractive-index geometrical optics.