Extrinsic chirality: tunable optically active reflectors and perfect absorbers

Conventional three-dimensionally (3D) chiral media can exhibit optical activity for transmitted waves, but optical activity for reflected waves is negligible. This work shows that mirror asymmetry of the experimental arrangement - extrinsic 3D chirality - leads to giant optical activity for reflected waves with fundamentally different characteristics. It is demonstrated experimentally that extrinsically 3D-chiral illumination of a lossy metasurface backed by a mirror enables tunable circular dichroism and circular birefringence as well as perfect absorption of circularly polarized waves. In contrast, such polarization phenomena vanish for conventional optically active media backed by a mirror

Optical Methods

Equilibrium optical melting curves are used in this unit to determine thermodynamic parameters of nucleic acid complex formation. This section contains all of the relevant equations and a discussion of which are most appropriate to a given situation. Additionally, procedures are given for making preliminary determinations of molar extinction coefficients and for determining the number of oligonucleotides in a complex. The section on extinction coefficients is particularly essential to anyone needing to know solution concentrations.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143743/1/cpnc0703.pd

Coherent control of Snell's law at metasurfaces

It was recently demonstrated that the well-known Snell's law must be corrected for phase gradient metasurfaces to account for their spatially varying phase, leading to normal and anomalous transmission and reflection of light on such metasurfaces. Here we show that the efficiency of normal and anomalous transmission and reflection of light can be controlled by the intensity or phase of a second coherent wave. The phenomenon is illustrated using gradient metasurfaces based on V-shaped and rectangular apertures in a metal film. This coherent control effect can be exploited for wave front shaping and signal routing

Research data for 'All-optical pattern recognition and image processing on a metamaterial beam splitter'

Research data for &#39;All-optical pattern recognition and image processing on a metamaterial beam splitter&#39;</span

Optomechanical guitar: reconfiguring metamaterials with sub-wavelength spatial resolution

Optomechanical metamaterials, where optical signals actuate unique elements of the nanostructure at their eigenfrequency, can be used to modulate metamaterials with sub-wavelength spatial resolution. We demonstrate the first all-optically addressable metadevice operating in the near infrared

Spatial optical phase-modulating metadevice with subwavelength pixelation

Dynamic control over optical wavefronts enables focusing, diffraction and redirection of light on demand, however, sub-wavelength resolution is required to avoid unwanted diffracted beams that are present in commercial spatial light modulators. Here we propose a realistic metadevice that dynamically controls the optical phase of reflected beams with sub-wavelength pixelation in one dimension. Based on reconfigurable metamaterials and nanomembrane technology, it consists of individually moveable metallic nanowire actuators that control the phase of reflected light by modulating the optical path length. We demonstrate that the metadevice can provide on-demand optical wavefront shaping functionalities of diffraction gratings, beam splitters, phase-gradient metasurfaces, cylindrical mirrors and mirror arrays — with variable focal distance and numerical aperture — without unwanted diffraction

All-optical image recognition using metamaterials

Coherent interaction of waves on a thin absorbing film allows performance of ultrafast, low energy logical functions with two-dimensional images, adaptive filtering and pattern recognition that we demonstrate with a plasmonic metamaterial absorber

Metadevice for intensity modulation with sub-wavelength spatial resolution

Research data for Cencillo Abad, Pablo, Zheludev, Nikolay and Plum, Eric (2016) Metadevice for intensity modulation with sub-wavelength spatial resolution. Scientific Reports, 6, 37109.</span