scholarly journals Sparsity-based continuous wave terahertz lens-free on-chip holography with sub-wavelength resolution

2019 ◽  
Vol 27 (2) ◽  
pp. 702 ◽  
Author(s):  
Zeyu Li ◽  
Qiang Yan ◽  
Yu Qin ◽  
Weipeng Kong ◽  
Guangbin Li ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Wavelength Resolution ◽  
On Chip ◽  
Sub Wavelength

scholarly journals Optofluidic Microscopy

2005 ◽  
Author(s):  
Xin Heng ◽  
David Erickson ◽  
Demetri Psaltis ◽  
Changhuei Yang
Keyword(s):  
Spatial Scaling ◽  
Power Sources ◽  
Lab On Chip ◽  
Fabrication Procedure ◽  
Wavelength Resolution ◽  
Imaging Theory ◽  
On Chip ◽  
Optofluidic Microscopy ◽  
Chip Analysis ◽  
Sub Wavelength

Recent advances in the development of lab-on-a-chip devices have been rapid and broad ranging. In general however these devices, while containing micro- or even nano-scale components, rely heavily on macroscale infrastructure (e.g. microscopes, chip readers and power sources) to perform much of the actual product detection and subsequent analysis. As such to enable the next generation of portable lab-on-chip devices, techniques for simply and cheaply integrating on-chip analysis functionalities will be required. In this work we present our work directed towards the development of a new concept in rapid on-chip imaging which we refer to as “optofluidic microscopy (OFM)”. Here we present an overview of the imaging theory, fabrication procedure and operational details of the initial prototype. Preliminary experimental results of this on-chip optical imager are also reported. A significant advantage of the technique is that through proper spatial scaling, sub-wavelength resolution can be achieved without bulk optics.

scholarly journals Roadmap of Terahertz Imaging 2021

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4092
Author(s):  
Gintaras Valušis ◽  
Alvydas Lisauskas ◽  
Hui Yuan ◽  
Wojciech Knap ◽  
Hartmut G. Roskos
Keyword(s):  
Room Temperature ◽  
Continuous Wave ◽  
Computational Imaging ◽  
Imaging Systems ◽  
Thz Imaging ◽  
Operational Conditions ◽  
Frequency Combs ◽  
Wave Imaging ◽  
On Chip ◽  
Nano Imaging

In this roadmap article, we have focused on the most recent advances in terahertz (THz) imaging with particular attention paid to the optimization and miniaturization of the THz imaging systems. Such systems entail enhanced functionality, reduced power consumption, and increased convenience, thus being geared toward the implementation of THz imaging systems in real operational conditions. The article will touch upon the advanced solid-state-based THz imaging systems, including room temperature THz sensors and arrays, as well as their on-chip integration with diffractive THz optical components. We will cover the current-state of compact room temperature THz emission sources, both optolectronic and electrically driven; particular emphasis is attributed to the beam-forming role in THz imaging, THz holography and spatial filtering, THz nano-imaging, and computational imaging. A number of advanced THz techniques, such as light-field THz imaging, homodyne spectroscopy, and phase sensitive spectrometry, THz modulated continuous wave imaging, room temperature THz frequency combs, and passive THz imaging, as well as the use of artificial intelligence in THz data processing and optics development, will be reviewed. This roadmap presents a structured snapshot of current advances in THz imaging as of 2021 and provides an opinion on contemporary scientific and technological challenges in this field, as well as extrapolations of possible further evolution in THz imaging.

scholarly journals Direct quantification of topological protection in symmetry-protected photonic edge states at telecom wavelengths

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Sonakshi Arora ◽  
Thomas Bauer ◽  
René Barczyk ◽  
Ewold Verhagen ◽  
L. Kuipers
Keyword(s):  
Near Field ◽  
Edge States ◽  
Quantum Networks ◽  
Hall Effects ◽  
Upper Limits ◽  
On Chip ◽  
Symmetry Protected ◽  
Topological Robustness ◽  
Direct Quantification ◽  
Sub Wavelength

AbstractTopological on-chip photonics based on tailored photonic crystals (PhCs) that emulate quantum valley-Hall effects has recently gained widespread interest owing to its promise of robust unidirectional transport of classical and quantum information. We present a direct quantitative evaluation of topological photonic edge eigenstates and their transport properties in the telecom wavelength range using phase-resolved near-field optical microscopy. Experimentally visualizing the detailed sub-wavelength structure of these modes propagating along the interface between two topologically non-trivial mirror-symmetric lattices allows us to map their dispersion relation and differentiate between the contributions of several higher-order Bloch harmonics. Selective probing of forward- and backward-propagating modes as defined by their phase velocities enables direct quantification of topological robustness. Studying near-field propagation in controlled defects allows us to extract upper limits of topological protection in on-chip photonic systems in comparison with conventional PhC waveguides. We find that protected edge states are two orders of magnitude more robust than modes of conventional PhC waveguides. This direct experimental quantification of topological robustness comprises a crucial step toward the application of topologically protected guiding in integrated photonics, allowing for unprecedented error-free photonic quantum networks.

Tunable nanoantennas with liquid crystals: dynamic wavefront control with sub-wavelength resolution

2021 ◽  
Author(s):  
Ramón J. Paniagua-Domínguez ◽  
Parikshit Moitra ◽  
Damien Eschimese ◽  
Rasna Maruthiyodan Veetil ◽  
Xuewu Xu ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Wavefront Control ◽  
Wavelength Resolution ◽  
Sub Wavelength

Magnetic modulation of Fano resonances in optically thin terahertz superlattice metasurfaces

2021 ◽  
Author(s):  
Subhajit Karmakar ◽  
Ravi Varshney ◽  
Dibakar Roy Chowdhury
Keyword(s):  
Magnetic Field ◽  
Free Space ◽  
Skin Depth ◽  
Electromagnetic Energy ◽  
Magnetic Control ◽  
Fano Resonances ◽  
Electromagnetic Responses ◽  
On Chip ◽  
Magneto Resistance ◽  
Sub Wavelength

Abstract Optically thin metasurfaces operating at sub-skin depth thicknesses are intriguing because of its associated low plasmonic losses (compared to optically thick, beyond skin-depth metasurfaces). However, their applicability has been restricted largely because of reduced free space coupling with incident radiations resulting in limited electromagnetic responses. To overcome such limitations, we propose enhancement of effective responses (resonances) in sub-skin depth metasurfaces through incorporation of magneto-transport (Giant Magneto Resistance, GMR) concept. Here, we experimentally demonstrate dynamic magnetic modulation of structurally asymmetric metasurfaces (consisting of superlattice arrangement of thin (~ 10 nm each) magnetic (Ni)/ nonmagnetic (Al) layers) operating at terahertz (THz) domain. With increasing magnetic field (applied from 0 to 30 mT approximately, implies increasing superlattice conductivity), we observe stronger confinement of electromagnetic energy at the resonances (both in dipole and Fano modes). Therefore, this study introduces unique magnetically reconfigurable ability in Fano resonant THz metamaterials, which directly improves its performances operating in the sub-skin depth regime. Our study can be explained by spin-dependent terahertz magneto-transport phenomena in metals and can stimulate the paradigm for on-chip spin-based photonic technology enabling dynamic magnetic control over compact, sub-wavelength, sub-skin depth metadevices.

Development of a Combined Scanning Ion-Conductance and Nearfield Optical Microscope to Image Living Cells

1999 ◽  
Vol 5 (S2) ◽  
pp. 976-977
Author(s):  
M. Raval ◽  
D. Klenerman ◽  
T. Rayment ◽  
Y. Korchev ◽  
M. Lab
Keyword(s):  
Optical Microscopy ◽  
Biological Samples ◽  
Near Field ◽  
Sample Surface ◽  
Optical Microscope ◽  
Ion Conductance ◽  
Simultaneous Generation ◽  
Simple Arrangement ◽  
Wavelength Resolution ◽  
Sub Wavelength

It is important to be able to image biological samples in a manner that is non-invasive and allows the sample to retain its functionality during imaging.A member of the SPM (scanning probe microscopy) family, SNOM (scanning near-field optical microscopy), has emerged as a technique that allows optical and topographic imaging of biological samples whilst satisfying the above stated criteria. The basic operating principle of SNOM is as follows. Light is coupled down a fibre-optic probe with an output aperture of sub-wavelength dimensions. The probe is then scanned over the sample surface from a distance that is approximately equal to the size of its aperture. By this apparently simple arrangement, the diffraction limit posed by conventional optical microscopy is overcome and simultaneous generation of optical and topographic images of sub-wavelength resolution is made possible. Spatial resolution values of lOOnm in air and 60nm in liquid[1,2] are achievable with SNOM.

Sub-wavelength resolution in linear arrays of plasmonic particles

2007 ◽  
Vol 101 (12) ◽  
pp. 123102 ◽  
Author(s):  
Constantin R. Simovski ◽  
Ari J. Viitanen ◽  
Sergei A. Tretyakov
Keyword(s):  
Linear Arrays ◽  
Wavelength Resolution ◽  
Sub Wavelength ◽  
Plasmonic Particles

scholarly journals Fourier optics approach to imaging with sub-wavelength resolution through metal-dielectric multilayers

2010 ◽  
Vol 18 (4) ◽  
Author(s):  
R. Kotyński
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Diffraction Theory ◽  
Spatial Filter ◽  
Fourier Optics ◽  
Point Spread ◽  
Spread Function ◽  
Point Spread Function Engineering ◽  
Wavelength Resolution ◽  
Sub Wavelength

AbstractMetal-dielectric layered stacks for imaging with sub-wavelength resolution are regarded as linear isoplanatic systems — a concept popular in Fourier optics and in scalar diffraction theory. In this context, a layered flat lens is a one-dimensional spatial filter characterised by the point spread function. However, depending on the model of the source, the definition of the point spread function for multilayers with sub-wavelength resolution may be formulated in several ways. Here, a distinction is made between a soft source and hard electric or magnetic sources. Each of these definitions leads to a different meaning of perfect imaging. It is shown that some simple interpretations of the PSF, such as the relation of its width to the resolution of the imaging system are ambiguous for the multilayers with sub-wavelenth resolution. These differences must be observed in point spread function engineering of layered systems with sub-wavelength sized PSF.

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