177 research outputs found
Orbital Angular Momentum Waves: Generation, Detection and Emerging Applications
Orbital angular momentum (OAM) has aroused a widespread interest in many
fields, especially in telecommunications due to its potential for unleashing
new capacity in the severely congested spectrum of commercial communication
systems. Beams carrying OAM have a helical phase front and a field strength
with a singularity along the axial center, which can be used for information
transmission, imaging and particle manipulation. The number of orthogonal OAM
modes in a single beam is theoretically infinite and each mode is an element of
a complete orthogonal basis that can be employed for multiplexing different
signals, thus greatly improving the spectrum efficiency. In this paper, we
comprehensively summarize and compare the methods for generation and detection
of optical OAM, radio OAM and acoustic OAM. Then, we represent the applications
and technical challenges of OAM in communications, including free-space optical
communications, optical fiber communications, radio communications and acoustic
communications. To complete our survey, we also discuss the state of art of
particle manipulation and target imaging with OAM beams
Recent advances in optical metasurfaces for polarization detection and engineered polarization profiles
Like amplitude, phase and frequency, polarization is one of the fundamental properties of light, which can be used to record, process and store information. Optical metasurfaces are ultrathin inhomogeneous media with planar nanostructures that can manipulate the optical properties of light at the subwavelength scale, which have become a current subject of intense research due to the desirable control of light propagation. The unprecedented capability of optical metasurfaces in the manipulation of the light’s polarization at subwavelength resolution has provided an unusual approach for polarization detection and arbitrary manipulation of polarization profiles. A compact metasurface platform has been demonstrated to detect polarization information of a light beam and to arbitrarily engineer a polarization profile that is very difficult or impossible to realize with conventional optical elements. This review will focus on the recent progress on ultrathin metasurface devices for polarization detection and realization of customized polarization profiles. Optical metasurfaces have provided new opportunities for polarization detection and manipulation, which can facilitate real-world deployment of polarization-related devices and systems in various research fields, including sensing, imaging, encryption, optical communications, quantum science, and fundamental physics
Optical metasurfaces for polarization generation, detection and imaging
Like phase and amplitude, polarization is a fundamental property of light, which can
reveal hidden information and has been used in many research fields, including material
science, medicine, target detection and biomedical diagnosis. Polarization generation,
detection and imaging are of importance for fundamental research and practical
applications. Although conventional optics can perform these tasks, it suffers from a
complex system, large volume and high cost, which cannot meet the continuing trend of
miniaturization and integration. Optical metasurfaces, the two-dimensional counterparts
of metamaterials, are planar nanostructured interfaces, which have recently attracted
tremendous interest in realizing ultrathin and lightweight planar optical devices. Optical
metasurfaces can manipulate light’s amplitude, phase and polarization in a desirable
manner, providing a new and compact platform to generate, detect and manipulate light’s
polarization. This thesis utilises optical metasurfaces to realise and experimentally
demonstrate novel optical devices for polarization generation, detection and imaging. Due
to the simplicity of the design and fabrication, this thesis is mainly focused on geometric
optical metasurfaces, which are superior to other types of metasurfaces.
2D and 3D polarization structures are generated based on a metalens approach. A ring
focal curve, an Archimedean spiral focal curve, and seven-segment-based decimal
numbers are experimentally demonstrated in 2D space, while a 3-foil knot, a 4-foil knot,
and a 5-foil are realized in 3D space. The geometric metasurfaces are designed based on
colour and phase multiplexing and polarization rotation, creating various 3D polarization
knots. Various 3D polarization knots in the same observation region can be achieved by
controlling the incident wavelengths, providing unprecedented polarization control with
colour information in 3D space. Novel polarization detection is experimentally
demonstrated through optical holography, light’s orbital angular momentum, and optical
ring vortex beams. The measured polarization parameters such as major axis, ellipticity,
and handedness are in good agreement with the theoretical prediction. A multifunctional
microscope is proposed and developed to image different objects, including biological
samples such as cheek cells and beef tendons. For the same sample, five images with
different optical properties are obtained on the same imaging plane, which can
simultaneously perform edge imaging, polarimetric imaging, and conventional
microscope imaging. Benefiting from the ultrathin nature, compactness and
multifunctionality of the optical metasurface devices, the integration does not excessively increase the volume of the optical system. With its promising capabilities and potential
for expandability, we believe our microscope will herald an exciting new era in
biomedical research.
The ultrathin nature of optical metasurfaces and their unprecedented capability in light
control have provided a compact platform to develop ultrathin optical devices with novel
functionalities that are very difficult or impossible to achieve with conventional optics.
The metasurface platform for polarization detection and manipulation is very attractive
for diverse applications, including polarization sensing and imaging, optical
communications, optical tweezers, quantum sciences, display technologies, and
biomedical research as well as wearable and portable consumer electronics and optics
where miniaturized systems are in high demand
Optical trapping with structured light : a review
Funding: This work was supported by the National Natural Science Foundation of China (11874102 and 61975047), the Sichuan Province Science and Technology Support Program (2020JDRC0006), and the Fundamental Research Funds for the Central Universities (ZYGX2019J102). M.C. and Y.A. thank the UK Engineering and Physical Sciences Research Council for funding.Optical trapping describes the interaction between light and matter to manipulate micro-objects through momentum transfer. In the case of 3D trapping with a single beam, this is termed optical tweezers. Optical tweezers are a powerful and noninvasive tool for manipulating small objects, and have become indispensable in many fields, including physics, biology, soft condensed matter, among others. In the early days, optical trapping was typically accomplished with a single Gaussian beam. In recent years, we have witnessed rapid progress in the use of structured light beams with customized phase, amplitude, and polarization in optical trapping. Unusual beam properties, such as phase singularities on-axis and propagation invariant nature, have opened up novel capabilities to the study of micromanipulation in liquid, air, and vacuum. We summarize the recent advances in the field of optical trapping using structured light beams.Publisher PDFPeer reviewe
Light, the universe and everything – 12 Herculean tasks for quantum cowboys and black diamond skiers
The Winter Colloquium on the Physics of Quantum Electronics (PQE) has been a seminal force in quantum optics and related areas since 1971. It is rather mind-boggling to recognize how the concepts presented at these conferences have transformed scientific understanding and human society. In January 2017, the participants of PQE were asked to consider the equally important prospects for the future, and to formulate a set of questions representing some of the greatest aspirations in this broad field. The result is this multi-authored paper, in which many of the world’s leading experts address the following fundamental questions: (1) What is the future of gravitational wave astronomy? (2) Are there new quantum phases of matter away from equilibrium that can be found and exploited – such as the time crystal? (3) Quantum theory in uncharted territory: What can we learn? (4) What are the ultimate limits for laser photon energies? (5) What are the ultimate limits to temporal, spatial and optical resolution? (6) What novel roles will atoms play in technology? (7) What applications lie ahead for nitrogen-vacancy centres in diamond? (8) What is the future of quantum coherence, squeezing and entanglement for enhanced super-resolution and sensing? (9) How can we solve (some of) humanity’s biggest problems through new quantum technologies? (10) What new understanding of materials and biological molecules will result from their dynamical characterization with free-electron lasers? (11) What new technologies and fundamental discoveries might quantum optics achieve by the end of this century? (12) What novel topological structures can be created and employed in quantum optics
Science Mission Directorate TechPort Records for 2019 STI-DAA Release
The role of the Science Mission Directorate (SMD) is to enable NASA to achieve its science goals in the context of the Nation's science agenda. SMD's strategic decisions regarding future missions and scientific pursuits are guided by Agency goals, input from the science community including the recommendations set forth in the National Research Council (NRC) decadal surveys and a commitment to preserve a balanced program across the major science disciplines. Toward this end, each of the four SMD science divisions -- Heliophysics, Earth Science, Planetary Science, and Astrophysics -- develops fundamental science questions upon which to base future research and mission programs
Computational and Numerical Simulations
Computational and Numerical Simulations is an edited book including 20 chapters. Book handles the recent research devoted to numerical simulations of physical and engineering systems. It presents both new theories and their applications, showing bridge between theoretical investigations and possibility to apply them by engineers of different branches of science. Numerical simulations play a key role in both theoretical and application oriented research
Satellite measurement of ocean turbulence
Turbulence and mixing in the surface layer of the ocean is a significant element in the combined ocean-atmosphere system, and plays a considerable role in the transfer of heat, gas and momentum across the air-sea boundary. Furthermore, improving knowledge of the evolution of energy within the ocean system, both globally and locally, holds importance for improving our understanding of the dynamics of the ocean at large- and small-scales. As such, insight into turbulence and turbulent flows at the ocean surface is becoming increasingly important for its role in ocean-atmosphere exchange and, from a wider perspective, climate change.A research project was initiated to understand the role that spacecraft remote-sensing may play in improving observation of “turbulence” (in a broad sense) in the ocean, and for identifying how steps towards such observation may be made. An initial, exploratory study identified the potential benefit of Synthetic Aperture Radar in “bridging the gap” between in-situ and remote observations o
Commonwealth of Independent States aerospace science and technology, 1992: A bibliography with indexes
This bibliography contains 1237 annotated references to reports and journal articles of Commonwealth of Independent States (CIS) intellectual origin entered into the NASA Scientific and Technical Information System during 1992. Representative subject areas include the following: aeronautics, astronautics, chemistry and materials, engineering, geosciences, life sciences, mathematical and computer sciences, physics, social sciences, and space sciences
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