17,505 research outputs found
Angular‐ and polarization‐independent structural colors based on 1D photonic crystals
Wide‐angle, polarization‐independent structural reflective colors from both directions based on a one‐dimensional photonic crystal are demonstrated. Our device produces a distinct and saturated color with high angular tolerant performance up to ±70° for any polarization state of an incident light wave, which is highly desirable for a broad range of research areas. Moreover, the purity of the color and luminous intensity of the proposed device are improved as compared to conventional colorant‐based color filters and colloidal glasses. The present approach may have the potential to replace existing color filters and pigments and pave the way for various applications, including color displays and image sensor technologies.A 1D photonic crystal‐based structural reflective color with angle‐invariant, polarization‐independent, and high‐purity characteristics is presented. Our proposed device is capable of creating a distinctive color that is insensitive with respect to the angle of incidence up to ±70° regardless of the polarization state of incident light. The presented approach can open the door to numerous applications, such as colored display technologies and imaging sensors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111776/1/lpor201500029.pd
Digital Color Imaging
This paper surveys current technology and research in the area of digital
color imaging. In order to establish the background and lay down terminology,
fundamental concepts of color perception and measurement are first presented
us-ing vector-space notation and terminology. Present-day color recording and
reproduction systems are reviewed along with the common mathematical models
used for representing these devices. Algorithms for processing color images for
display and communication are surveyed, and a forecast of research trends is
attempted. An extensive bibliography is provided
Measurement and evaluation of the applicability of reflective displays for direct view applications
A measurement set-up is presented to analyse the applicability of reflective displays for direct view applications. Essential for this set-up is to simulate the different types of illumination caused by environmental light. As an example the applicability of a reflective PNLC display is evaluated
Attributing scientific and technical progress: the case of holography
Holography, the three-dimensional imaging technology, was portrayed widely as a paradigm
of progress during its decade of explosive expansion 1964–73, and during its subsequent
consolidation for commercial and artistic uses up to the mid 1980s. An unusually
seductive and prolific subject, holography successively spawned scientific insights, putative
applications and new constituencies of practitioners and consumers. Waves of forecasts,
associated with different sponsors and user communities, cast holography as a field on the
verge of success—but with the dimensions of success repeatedly refashioned. This retargeting
of the subject represented a degree of cynical marketeering, but was underpinned by
implicit confidence in philosophical positivism and faith in technological progressivism.
Each of its communities defined success in terms of expansion, and anticipated continual
progressive increase. This paper discusses the contrasting definitions of progress in holography,
and how they were fashioned in changing contexts. Focusing equally on reputed ‘failures’ of some aspects of the subject, it explores the varied attributes by which success and failure were linked with progress by different technical communities. This important case illuminates the peculiar post-World War II environment that melded the military, commercial and popular engagement with scientific and technological subjects, and the
competing criteria by which they assessed the products of science
Gradient metasurfaces: a review of fundamentals and applications
In the wake of intense research on metamaterials the two-dimensional
analogue, known as metasurfaces, has attracted progressively increasing
attention in recent years due to the ease of fabrication and smaller insertion
losses, while enabling an unprecedented control over spatial distributions of
transmitted and reflected optical fields. Metasurfaces represent optically thin
planar arrays of resonant subwavelength elements that can be arranged in a
strictly or quasi periodic fashion, or even in an aperiodic manner, depending
on targeted optical wavefronts to be molded with their help. This paper reviews
a broad subclass of metasurfaces, viz. gradient metasurfaces, which are devised
to exhibit spatially varying optical responses resulting in spatially varying
amplitudes, phases and polarizations of scattered fields. Starting with
introducing the concept of gradient metasurfaces, we present classification of
different metasurfaces from the viewpoint of their responses, differentiating
electrical-dipole, geometric, reflective and Huygens' metasurfaces. The
fundamental building blocks essential for the realization of metasurfaces are
then discussed in order to elucidate the underlying physics of various physical
realizations of both plasmonic and purely dielectric metasurfaces. We then
overview the main applications of gradient metasurfaces, including waveplates,
flat lenses, spiral phase plates, broadband absorbers, color printing,
holograms, polarimeters and surface wave couplers. The review is terminated
with a short section on recently developed nonlinear metasurfaces, followed by
the outlook presenting our view on possible future developments and
perspectives for future applications.Comment: Accepted for publication in Reports on Progress in Physic
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