scholarly journals A Closer Look at Photonic Nanojets in Reflection Mode: Control of Standing Wave Modulation

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 54
Author(s):  
Ksenia A. Sergeeva ◽  
Alexander A. Sergeev ◽  
Oleg V. Minin ◽  
Igor V. Minin
Keyword(s):  
Aluminum Oxide ◽  
Standing Wave ◽  
Optical Devices ◽  
Reflection Mode ◽  
Constructive Interference ◽  
Entire Class ◽  
Photonic Nanojet ◽  
New Type ◽  
Photonic Nanojets ◽  
Illumination Source

The photonic nanojet phenomenon is commonly used both to increase the resolution of optical microscopes and to trap nanoparticles. However, such photonic nanojets are not applicable to an entire class of objects. Here we present a new type of photonic nanojet in reflection mode with the possibility to control the modulation of the photonic nanojet by a standing wave. In contrast to the known kinds of reflective photonic nanojets, the reported one occurs when the aluminum oxide hemisphere is located at a certain distance from the substrate. Under illumination, the hemisphere generates a primary photonic nanojet directed to the substrate. After reflection, the primary nanojet acts as an illumination source for the hemisphere, leading to the formation of a new reflective photonic nanojet. We show that the distance between the hemisphere and substrate affects the phase of both incident and reflected radiation, and due to constructive interference, the modulation of the reflective photonic nanojet by a standing wave can be significantly reduced. The results obtained contribute to the understanding of the processes of photonic nanojet formation in reflection mode and open new pathways for designing functional optical devices.

Photonic Nanojet Generation in Transmission and Reflection Mode

2020 ◽  
Vol 312 ◽  
pp. 213-220
Author(s):  
Alexander A. Sergeev ◽  
Ksenia A. Sergeeva ◽  
Aleksandr Vladimirovich Nepomniaschiy ◽  
Sergey S. Voznesenskiy
Keyword(s):  
Functional Performance ◽  
Gaseous Ammonia ◽  
The Novel ◽  
Reflection Mode ◽  
Sensitive Layer ◽  
Photonic Nanojet ◽  
Sensor Structure ◽  
Ammonia Detection ◽  
Photonic Nanojets ◽  
Transmission And Reflection

This paper is related to the problem of enhancing the optical and functional performance of luminescent gas sensors via its excitation by photonic nanojets. The novel sensor structure consisting of the array of alumina microparticles covered by optical sensitive layer was designed. The parameters of the photonic nanojets generated in both transmission and reflection modes has been numerically end experimentally studied. It was shown that PNJ in reflection mode demonstrates an unexpectedly high enhancement of photoluminescence. It was obtained that the excitation of the sensitive layer by photonic nanojets extends the limit of gaseous ammonia detection up to 0.1 ppm for reflection mode and up to 0.02 ppm for transmission mode.

scholarly journals New Types of Doubly Periodic Standing Wave Solutions for the Coupled Higgs Field Equation

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Gui-qiong Xu
Keyword(s):  
Field Equation ◽  
Standing Wave ◽  
Higgs Field ◽  
Jacobi Elliptic Function ◽  
Bilinear Method ◽  
Wave Solutions ◽  
New Type ◽  
Function Expression ◽  
Parameter Values ◽  
Hirota Bilinear

Based on the Hirota bilinear method and theta function identities, we obtain a new type of doubly periodic standing wave solutions for a coupled Higgs field equation. The Jacobi elliptic function expression and long wave limits of the periodic solutions are also presented. By selecting appropriate parameter values, we analyze the interaction properties of periodic-periodic waves and periodic-solitary waves by some figures.

scholarly journals Large-Scale Fabrication of Photonic Nanojet Array via Template-Assisted Self-Assembly

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 473 ◽  
Author(s):  
Pengcheng Zhang ◽  
Xi Chen ◽  
Hui Yang
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
Super Resolution ◽  
Light Signal ◽  
Practical Applications ◽  
Photonic Nanojet ◽  
Detection Technology ◽  
Size Uniformity ◽  
Resolution Imaging ◽  
Photonic Nanojets

A large-scale homogenized photonic nanojet array with defined pattern and spacing facilitates practical applications in super-resolution imaging, subwavelength-resolution nanopatterning, nano objects trapping and detection technology. In this paper, we present the fabrication of a large-scale photonic nanojet array via the template-assisted self-assembly (TASA) approach. Templates of two-dimensional (2D) large-scale microwell array with defined pattern and spacing are fabricated. Melamine microspheres with excellent size uniformity are utilized to pattern on the template. It is found that microwells can be filled at a yield up to 95%. These arrayed microspheres on the template serve as microlenses and can be excited to generate large-scale photonic nanojets. The uniformly-sized melamine spheres are beneficial for the generation of a homogenized photonic nanojet array. The intensity of the photonic nanojets in water is as high as ~2 fold the background light signal. Our work shows a simple, robust, and fast means for the fabrication of a large-scale homogenized photonic nanojet array.

An RF spectrometer for fast wide band measurement

2009 ◽  
Vol 1 (6) ◽  
pp. 537-542 ◽  
Author(s):  
Simon Hemour ◽  
Florence Podevin ◽  
Pascal Xavier
Keyword(s):  
Fourier Transform ◽  
Standing Wave ◽  
Short Circuit ◽  
Wide Band ◽  
Stationary Wave ◽  
Fourier Transform Spectrometer ◽  
Wideband Signals ◽  
New Type ◽  
5 Ghz ◽  
Proof Of Principle

A new type of spectrum analyzer using RF interferometry is presented. The stationary wave integrated Fourier transform spectrometer is dedicated to the measurement of transient wideband signals. The spectrometer is mobile and cheap. It consists of spatial samplers placed along a waveguide ended by a short circuit. The standing wave caused by the short circuit is sampled and the spectrum is obtained by an FFT computation. A 0.3–5 GHz analyzer was built as a proof-of-principle demonstration and an application to RF dosimetry is shown.

Design of the Real-Time Autofocusing System for Collimator with Long Focus Length and Large Aperture

2011 ◽  
Vol 127 ◽  
pp. 25-31
Author(s):  
Xiang Li ◽  
Xiao Hui Zhang
Keyword(s):  
Computer Simulation ◽  
Semiconductor Lasers ◽  
Essential Role ◽  
Focal Length ◽  
Optical Devices ◽  
Plane Mirror ◽  
Large Aperture ◽  
Surrounding Environment ◽  
New Type ◽  
Common Problems

Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment, the large aperture collimator’s accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However, the process of adjusting the collimator is extremely complicated due to the collimator’s large aperture and long focal length. So it is difficult to ensure the measurement’s quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above, this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror, semiconductor lasers as light source and CCD sensor as receiver. The system is smaller, lighter, and more convenient when using. The computer simulation shows that the autofocusing system’s resolution could reach the accuracy of 40μm. If we use the relevant algorithms to execute the sub-pixel scanning, the resolution could reach the accuracy of 10μm. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

Visualization of the Microtubules of Glutaraldehyde-Fixed Cells by Reflection-Enhanced Backscatter Confocal Microscopy

2005 ◽  
Vol 12 (2) ◽  
pp. 113-123
Author(s):  
Charles H. Keith ◽  
Mark A. Farmer
Keyword(s):  
Confocal Microscopy ◽  
Fluorescence Microscopy ◽  
Standing Wave ◽  
Reflection Mode ◽  
Intact Cells ◽  
Fluorescence Techniques ◽  
Number Of Factors

Performing reflection-mode (backscatter-mode) confocal microscopy on cells growing on reflective substrates gives images that have improved contrast and are more easily interpreted than standard reflection-mode confocal micrographs (Keith et al., 1998). However, a number of factors degrade the quality of images taken with the highest-resolution microscope objectives in this technique. We here describe modifications to reflection-enhanced backscatter confocal microscopy that (partially) overcome these factors. With these modifications of the technique, it is possible to visualize structures the size—and refractility—of individual microtubules in intact cells. Additionally, we demonstrate that this technique, in common with fluorescence techniques such as standing wave widefield fluorescence microscopy and 4-Pi confocal microscopy, offers improved resolution in the Z-direction.

scholarly journals The photonic nanojets formation by two-dimensional microprisms

2020 ◽  
Vol 44 (6) ◽  
pp. 909-916
Author(s):  
V.D. Zaitsev ◽  
S.S. Stafeev
Keyword(s):  
Barium Titanate ◽  
Focal Spot ◽  
Incident Radiation ◽  
Maximum Intensity ◽  
Two Dimensional ◽  
Scalar Diffraction ◽  
Photonic Nanojet ◽  
Triangular Profile ◽  
Photonic Nanojets ◽  
Base Width

Using the finite difference method implemented in the COMSOL Multiphysics software package, the focusing of laser radiation by dielectric prisms with a triangular profile was numerically investigated. It was shown that two-dimensional triangular prisms make it possible to focus light in free space into spots with dimensions smaller than the scalar diffraction limit. In particular, a silica glass prism with a base width of 60 μm and a height of 28.5 μm forms a photonic nanojet with a maximum intensity of 6 times the intensity of the incident radiation and a width of FWHM=0.38λ. A prism from barium titanate with a base width of 60 μm and a height of 20 μm allows to obtain a photonic nanojet with the same width (0.38λ) and a maximum intensity 5 times the intensity of the incident radiation. The size of the focal spot can be reduced further if the height of the prism is selected so that the maximum intensity is located inside the material of the prism. For example, a barium titanate prism with a height of 21 μm and a base width of 60 μm forms a focal spot with a width of FWHM=0.25λ.

Anomalous Optical Transmission Phenomena in Photonic Crystals

2013 ◽  
Vol 320 ◽  
pp. 128-132
Author(s):  
Guo Yan Dong ◽  
Ji Zhou
Keyword(s):  
Electromagnetic Wave ◽  
Photonic Crystals ◽  
Optical Transmission ◽  
Electromagnetic Wave Propagation ◽  
Negative Refraction ◽  
Optical Devices ◽  
Honeycomb Lattice ◽  
Equal Frequency ◽  
Left Handed ◽  
New Type

Anomalous optical transmission phenomena have ever been discovered in various metamaterials, which can be modulated more easily in Photonic crystals (PhCs). Compared with the regular PhCs composed of round rods closely packed in air, the equal frequency contours (EFC) of honeycomb lattice PhCs constituted by trigonal rods are more rounded and more suitable to realize the all-angle left-handed negative refraction (AALNR) in the low band region. Due to the hex EFC distribution, the regular PhC can be applied in the optical collimator design. In the higher band regions, the more complicated refraction behaviors can be excited based on the intricate undulation of one band or the overlap of different bands in PhCs. These unique features will provide us with more understanding of electromagnetic wave propagation in PhCs and give important guideline for the design of new type optical devices.

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