We have synthesized spinnable carbon nanotube (CNT) [1] and have developed the CNT strain sensors as components of a textile based, wearable sensing system for real-time motion detection [2]. The aligned CNT layer was formed by stacking CNT webs drawn from a spinnable CNT forest. In the strain sensors, we sandwiched the aligned CNT sheet between elastomer layers. We have applied the CNT strain...
An intense femtosecond laser pulse propagating in air undergoes a filamentation process, during which beam self-focusing due to the optical Kerr effect is counterbalanced by beam defocusing due to plasma generation. As a consequence, the propagating laser pulse maintains a high intensity over very long distances. I will describe some applications exploiting this effect. It includes remote...
First, the current state of national universities in Japan will be explained. On top of that, we will discuss the future direction of local universities in Japan, where declining birthrate and population continue. Even for local universities, having strengths is important to promote research and industry-academia collaboration for survival.
Shizuoka University's Hamamatsu Campus will...
An overview of imaging methods involving neutrons or synchrotron radiation at large scale facilities and their application to the investigation of magnetic materials is given. Dynamic neutron imaging experiments analysing the behaviour of paramagnetic liquids in magnetic field gradients are presented. Furthermore, an introduction to the study of magnetic nanostructures with microspectroscopic...
Remote collection and analysis of light is highly important for a plethora of applications including spectroscopy, endoscopy, biosensing, quantum communications, etc. Commercial optical fibers are the best platform for this purpose due to their ability to operate in strongly limited and closed spaces (particularly, in-vivo) in a wide range of environments and external conditions. The payback...
Metasurface is a periodic subwavelength array of scatterers that provides effective beam shaping, phase and polarization manipulation of electromagnetic waves. In contrast to bulk metamaterials, metasurfaces allow eliminating volumetric losses, simplifying the manufacturing process, and ensuring full integration into optical planar devices. They can serve as various optical devices including...
We investigate the relaxation dynamics of a plasma channel, called filament, produced in air by an intense femtosecond laser pulse. A single-cycle terahertz pulse, generated by a secondary air-plasma, probes the filament at its near-critical plasma density.
We investigate essential parameters of the plasma filament, especially the electron density, in the particular regime of high...
Intense picosecond terahertz radiation has opened new opportunities in solid-state physics and materials science, allowing to probe and/or control different degrees of freedom of a solid by driving electrons, magnons, or phonons at ultrafast timescales with an intense electric field associated with photon energy in the meV range1. Owing to significant spectral weight in the...
DNA point accumulation for imaging in nanoscale topography (DNA-PAINT)[1] is a powerful super-resolution technique highly suitable for multi-target (multiplexing) bio-imaging. However, multiplexed imaging of cells is still challenging due to the dense and sticky environment inside a cell. Here, we combine fluorescence lifetime imaging microscopy (FLIM) with DNA-PAINT and use the lifetime...
Despite the significant achievements of biophysical science, many mechanisms of interaction between biological molecules and external agents (medicines) are not explained. There are many different approaches to the study of the interaction of proteins with drugs. One of them is a study of the spectral properties of π-conjugated amino acids (tyrosine, tryptophan, phenylalanine), which absorb...
Reservoirs of lipid molecules, specifically onion shell vesicles, spread on high energy surfaces, e.g. SiO2, to form a stack of molecular films (double bilayer). Eventually, the spreading lipid exhausts the reservoir, and rising tension ruptures the films. Köksal et al. discovered that this disruptive process generates a network of nanotubes, which redistributes lipid material in order to...
X-ray image have been developed for medical and non-destructive inspection, and higher resolution and larger area detectors are required due to the development of technology. Therefore, in this study, the spatial resolution of a scintillation type image detector, which is an indirect conversion type X-ray image detector can be easily enlarged has been improved. The cause of lowering the...
Fusion reactions, such as the D-D and D-T reactions, can be used to produce neutrons in smaller devices than conventional neutron sources such as nuclear reactors and large accelerators. Compared to conventional methods, this neutron source enables to make imaging devices smaller and more convenient.
The Small-scale neutron imaging device is consisted of a neutron source, detectors, and other...
Thallium bromide is a compound semiconductor with high atomic number and density and wide bandgap. Therefore, thallium bromide has potential as a direct conversion type radiation detector that can operate at room temperature.
One application for semiconductor detectors is for low-energy X-ray applications such as mammography and pathology, where the high stopping power of thallium bromide...
X-ray imaging technology has applications in medicine, nondestructive testing at industrial sites, and security inspections at airports.
Today, semiconductor detectors are widely used as radiation detectors. Because semiconductor detectors convert X-rays directly into electric charge, they are considered to have higher spatial resolution than scintillator-type detectors, which convert X-rays...
CdTe has been used as radiation detectors at room temperature. Impurity doping of CdTe has been considered difficult because it requires high temperature heat treatment and characteristics are degraded. However, the laser doping method that we have recently developed is overcoming this problem. When doping semiconductors, not all dopants act as donors or acceptors, and some of them become...
Compared to scintillator detectors, semiconductor detectors have higher spatial resolution because of the direct generation of electric charge when X-rays are incident inside the semiconductor. Among semiconductor detectors, CdTe semiconductor detectors are used as radiation detectors at room temperature. Since the thickness of the CdTe device used as a radiation detector is as thick as...
The comprehensive knowledge of the mechanism involved in the charge carrier separation in nanoscale structures is of high interest regarding applications and fundamental researches. A microscopy technique that enables the visualization of subpicosecond carrier dynamics in nanometer-scale structures is laser-combined scanning tunneling microscopy [1]. OptoPulSTM simultaneously realizes STM...
In the talk, diverse scenarios of invisibility will be reviewed and exemplified. Extensive development of invisibility cloaks which can make good scatterers invisible has been mainly connected with the raise of metamaterials in the early 2000s. Metamaterials enable Transformation Optics offering such desired distributions of the material parameters of the cloak, a specific coating of the...
The time-domain terahertz (THz) spectroscopy has proven to be a powerful technique for investigation of the ultrafast electron transport. In this talk, it will be shown that it can also evidence the ultrafast dynamics of spin currents: their generation, spin-to-charge conversion and relaxation in conventional spintronic metals, as well as compensated magnetic materials or van der Waals...
A nitrogen gas pumped by near-infrared femtosecond pulses gives rise to a coherent emission at 391.4 nm due to transitions between ionic levels. For the first time, we experimentally analyze the temporal evolution of the populations of N$_2^+$ levels involved in this lasing process. To visualize this dynamics, we measure the transmission of a high harmonics source through N$_2^+$.
One of the most challenging tasks for LED applications is emitting 100% polarized light from the device. Typically, this is achieved by introducing an additional layer of polarization filter which leads to losing half of the light intensity. To overcome this issue, one has to find a system with a high degree of photoluminescence (PL) polarization. A promising approach here is using magnetic...
Antiferromagnets (AFMs) are promising materials for spintronic and opto-electronic applications due to natural spin dynamics in the THz range and, at the same time, they have no net magnetization. This leads to the absence of stray fields which is a useful property for data storage applications. A promising approach here is to combine the unique magnetic properties of AFMs with the strong...
Lead-halide perovskite nanocrystals have emerged as high-performance semiconductors for efficient optoelectronic devices, especially in light-emitting diodes (LEDs) for bright and flexible displays. Atomic doping with transition metals other than lead has been shown to dramatically boost the luminescence of these nanocrystals. Yet, we still do not fully understand why these materials work so...
Two-dimensional infrared (2DIR) spectroscopy has been widely used in structure study and energy transfer of bulk samples. However, in the last decade, 2DIR spectroscopy has been extended to study molecules at interfaces. Our target was to develop a user-friendly 2D ATR IR spectrometer, which will benefit a broad group of laboratories and researchers, expanding the borders of regular 2DIR...
Demand for X-ray inspection has been increasing in recent years, and research in advanced fields is progressing, including the development of high-definition X-ray CT. On the other hand, since the human eye can only spatially grasp the surface information of a three-dimensional object, the three-dimensional information captured by X-ray CT is confirmed as images from three directions:...
Currently, X-rays are used in a variety of places by taking advantage of their penetrating effect, such as X-ray imaging and CT inspection in the medical field, and non-destructive testing field, and security field such as baggage inspections at airports. On the other hand, when taking image with X-rays, due to the fact that X-rays are invisible light, it takes much time on alignment, the...
X-ray CT is a technique to visualize the distribution of the X-ray attenuation coefficient inside an object and has a wide range of applications, such as nondestructive testing, medical examination, and intraoperative assessment. In general, the attenuation of X-rays depends on the energy of the X-ray photon and the material they penetrate; the X-ray spectrum will be different when it...
Type I Half-Logistic Rayleigh distribution is a new development distribution. The main objective of this study is to estimate parameter under Bayesian approach using Lindley’s method with two different loss functions and maximum likelihood estimation (MLE). The two loss functions used are squared error loss function (SELF) and linear exponential (LINEX) loss function. Reliability and hazard...
In recent years, the ability of X-rays to detect buried objects has led to calls for the detection of land mines buried underground and the inspection of aging reinforcing steel bars in aging buildings. In this study, A method called reflection x-ray imaging is used, in which X-rays are irradiated onto a target and the reflected X-rays are detected. Reflected X-ray imaging can detect objects...
The Photon Counting in Sinogram of CT is according to the Poisson distribution of X-ray photons. And every Sinogram contains the components of Pixel imaging, and every components receive the photons. So the numbers of photons in the components are the random numbers according to the Poisson distribution. Adding these random numbers, that is Sinogram become to the random numbers according to...
Ge detectors are widely used as X-ray/γ-ray detectors, but they cannot operate at room temperature due to narrow bandgap, must be cooled with liquid nitrogen. As a better material, CdTe, which can operate at room temperature and has a large attenuation coefficient, is becoming more widely used. However, compared to Ge, the manufacturing process has not been optimized and the manufacturing cost...
BT.2020's color gamut includes 99.9% of that of Pointer colors, which is colorimetric data representing the gamut of real surface colors. For this reason, BT.2020 compliant Ultra High Definition (UHD) displays are required to have a wider color gamut than High Definition (HD) displays. Light-emitting devices and color filters are being developed for UHD displays. Due to issues with...
This paper presents theoretical study of phenomenon of stimulated Brillouin scattering of q-Gaussian laser beams in nonlinearly-interacting with underdense plasmas. During propagation of intense laser beam with ω0, it gets coupled to pre-existing ion acoustic wave (IAW) at frequency ωia due to relativistic mass nonlinearity of plasma electrons. The nonlinear interaction of pump beam with IAW...
The phenomenon of stimulated Raman scattering (S.R.S) of intense self focused Cosh-Gaussian (ChG) laser beams in underdense plasma targets modeled by a ramp shaped different density profiles, has been investigated. An intense laser beam with frequency ω0 propagating through plasma gets coupled with a pre-existing electron plasma wave (EPW) at frequency ωep and produces a back scattered wave...
LIBS (Laser-Induced Breakdown Spectroscopy) allows to measure the concentration of major and trace elements in solid, liquid, or air samples. LIBS technology has the advantage of adapting the research to any situation, from online measurements in an industrial environment to analyses in the laboratory.
LIBS technology is designed to meet detection and analysis needs in a wide variety of...
Theoretical study on electron acceleration by intense laser beams
in thermal quantum plasmas has been presented. In order to enhance the interaction of accelerated electrons with the laser beam the irradiance over the beam cross
section has been modeled by Cosh Gaussian (ChG) profile. Effect of self focusing of the laser beam on energy gained by the electrons has been investigated in detail....
Further progress in the field of creating functional and multifunctional nanostructured materials and coatings is associated, both with the development of industrial technologies for their production and with the certification of methods for measuring the mechanical properties of nanomaterials. Determination of mechanical properties plays a primary role in the design of new nanomaterials,...
Theoretical investigation on self focusing of an elliptical -Gaussian laser beam carrying an intensity ripple over its cross section, in plasma with axial density ramp has been presented. The optical nonlinearity of plasma has been modeled by the relativistic mass nonlinearity of plasma electrons in the field of laser beam. Using Variational theory approach, semi analytical solutions of the...
A scheme for second-harmonic generation (SHG) of a pair of q-Gaussian laser beams interacting nonlinearly with underdense plasma has been proposed. Due to the relativistic increase in electron mass under the intense fields of the laser beam, the resulting optical nonlinearity of plasma leads cross-focusing of the laser beams. The resulting nonlinear coupling between the two laser beams makes...
Copper mirrors, which were deposited by various technologies, were investigated in the work. The basis for the mirrors was a ceramic substrate made by sintering and pressing silicon carbide. The working layer of copper with a thickness of 0.25-0.30 mm was applied by vacuum or galvanic deposition. After applying the copper layer, the reflective surface was formed by diamond microturning....
Right after the discovery of high temperature superconductivity in 1986 it has provided a new path for scientific enquiry. In 1986, it was discovered that some cuprate-perovskite ceramic materials have a critical temperature above 90 K. For conventional superconductors such a high transition temperature is theoretically not possible. Right now we know only about their nature, however there are...
The investigation of the influence of various chemical substances on the properties of the surface layer of porous silicon is relevant for the creation of sensors of gaseous and liquid impurities. In work, the decoration by isopropyl alcohol of the surface of the porous silicon with different porosity was studied by ellipsometry. The obtained ellipsometric data were processed in a...
Optical properties of the rapidly quenched ribbons of the Fe-based amorphous alloys in the infrared $\lambda$ = 2–25 $\mu$m were studied by spectral ellipsometry. The ellipsometric parameters $\Delta$ and $\Psi$ were measured for several azimuthal directions $\alpha$ in own plane of the samples to detect of its optical anisotropy. The frequency dependencies of the real $\epsilon_1$ and...
The covid pandemic that has taken over the world since 2019 has shown the need for the development of remote patient monitoring and control systems. The need to protect personnel from contamination has led to the use of various methods of disinfection of medical and sanitary facilities in which patients (staff) may be at the time of treatment.
All these problems that humanity faced at that...
There are many ways to protect nanocrystals from degradation and to improve NC properties. One of the most promising is embedding NCs in polymer matrices. NCs in transparent polymers is perspective material for applications in photonics and bio-imaging, thus investigation of their light-emitting properties is important. While NCs in conductive polymers attracts considerable attention due to...
The effect of plasmonic nanoparticles (NPs) on Raman spectra and underlying structural changes in thin chalcogenide films are investigated. As2S3 and Se films with a thickness of several tens of nanometers were deposited by thermal sputtering for comparison on ordinary glass and SERS substrates based on arrays of gold nanostructures. Films on glass are practically not detectable by Raman...
One of the trends for the future of renewable energy is the use of materials that can combine photovoltaic and thermoelectric properties in hybrid solar cells. These materials should also fulfill a number of other requirements. For instance, they should have a bandgap suitable for photovoltaics and constituent elements should be abundant and non-toxic. All these requirements are covered by the...
