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The temperature measurement of material inside of an object is one of the key technologies for control of dynamical processes. For this purpose, various techniques such as laser-based thermography and phase-contrast imaging thermography have been studied. However, it is, in principle, impossible to measure the temperature of an element inside of an object using these techniques. One of the possible solutions is measurements of Doppler brooding effect in neutron resonance absorption (NRA). Here we present a method to measure the temperature of an element or an isotope inside of an object using NRA with a single neutron pulse of approximately 100 ns width provided from a high-power laser. We demonstrate temperature measurements of a tantalum (Ta) metallic foil heated from the room temperature up to 617 K. Although the neutron energy resolution is fluctuated from shot to shot, we obtain the temperature dependence of resonance Doppler broadening using a reference of a silver (Ag) foil kept to the room temperature. A free gas model well reproduces the results. This method enables element(isotope)-sensitive thermometry to detect the instantaneous temperature rise in dynamical processes. Non-contact thermometry is one of the key technologies for modern science and industry. Here, authors demonstrated measurement of temperature of an element using neutron resonance spectroscopy with Doppler broadening with single intense short neutron pulse provided from high peak power.

A wide variety of optical components are used in optical instruments such as laser devices, spectrophotometers, cameras and telescopes. To enhance their performance, these components are often coated with optical thin films including antireflection (AR) coatings, high reflection (HR) coatings, polarizing films, translucent films, and bandpass filters. However, the fabrication of multilayer thin-film coatings is often constrained by stresses that arise during the deposition process. These stresses can lead to delamination, thereby limiting the range of dielectric materials and operating wavelengths available for optical components. We report a novel thin-film fabrication method that enables both refractive index control and significant stress reduction. This approach produces adaptively mixed thin films (AMTFs), consisting of dielectric material, polytetrafluoroethylene (PTFE), and depletion layers, with a porous microstructure that lowers refractive index while maintaining high transmittance. For example, AMTF: MgF₂ films exhibit a refractive index as low as 1.3, a 15-fold reduction in stress compared with pure MgF₂, and 95.95% transmittance. In addition to antireflection coatings, highly reflective multilayer mirrors can also be fabricated using structures such as [Al₂O₃/AMTF: Al₂O₃], [ZrO₂/AMTF: SiO₂], and [TiO₂/AMTF: MgF₂]. The range of applicable dielectric materials is thereby significantly expanded. By tailoring the refractive index, these films enable coverage of a broad spectral range from 200 nm to 7000 nm. The demonstrated reduction of stress, control over refractive index, and wide spectral applicability highlight the potential of AMTFs to advance the design and fabrication of next-generation optical coatings, particularly in the field of laser optics.

This study introduces a fragmentation-based linear-scaling method for strongly correlated systems, specifically the divide-and-conquer Hartree–Fock–Bogoliubov (DC-HFB) approach. Two energy gradient formulations of the DC-HFB method are derived and implemented, enabling efficient optimization of molecular geometries in large systems. This method is applied to graphene nanoribbons (GNRs) to explore their geometries and polyradical characters. Numerical results demonstrate that the present DC-HFB method has the potential to treat the static electron correlation and predict diradical character in GNRs, offering new avenues for studying large-scale strongly correlated systems.

Fast isochoric heating of a pre-compressed plasma core with a high-intensity short-pulse laser is an attractive and alternative approach to create ultra-high-energy-density states like those found in inertial confinement fusion (ICF) ignition sparks. Laser-produced relativistic electron beam (REB) deposits a part of kinetic energy in the core, and then the heated region becomes the hot spark to trigger the ignition. However, due to the inherent large angular spread of the produced REB, only a small portion of the REB collides with the core. Here, we demonstrate a factor-of-two enhancement of laser-to-core energy coupling with the magnetized fast isochoric heating. The method employs a magnetic field of hundreds of Tesla that is applied to the transport region from the REB generation zone to the core which results in guiding the REB along the magnetic field lines to the core. This scheme may provide more efficient energy coupling compared to the conventional ICF scheme. It is desirable to deposit more energy in the dense plasma core to trigger the fusion ignition. Here the authors demonstrate enhanced energy coupling from laser to plasma core by using solid targets and guiding the transport of relativistic electron beam with external magnetic field.

Meteorites from interplanetary space often include high-pressure polymorphs of their constituent minerals, which provide records of past hypervelocity collisions. These collisions were expected to occur between kilometre-sized asteroids, generating transient high-pressure states lasting for several seconds to facilitate mineral transformations across the relevant phase boundaries. However, their mechanisms in such a short timescale were never experimentally evaluated and remained speculative. Here, we show a nanosecond transformation mechanism yielding ringwoodite, which is the most typical high-pressure mineral in meteorites. An olivine crystal was shock-compressed by a focused high-power laser pulse, and the transformation was time-resolved by femtosecond diffractometry using an X-ray free electron laser. Our results show the formation of ringwoodite through a faster, diffusionless process, suggesting that ringwoodite can form from collisions between much smaller bodies, such as metre to submetre-sized asteroids, at common relative velocities. Even nominally unshocked meteorites could therefore contain signatures of high-pressure states from past collisions. Meteorites from space often include denser polymorphs of their minerals, providing records of past hypervelocity collisions. An olivine mineral crystal was shock-compressed by a high-power laser, and its transformation into denser ringwoodite was time-resolved using an X-ray free electron laser.

Recent research and development into the formation of nanoscale channels as a central component of nanofluidic biochip systems revolutionized the biological and chemical fields. Exploration of new pathways to form nanochannels is increasingly necessary to provide a new generation of analytical tools with accurate control of liquid fluid flow, high selectivity and increased mass flow rate. Here, we demonstrate that a single 9-keV pulse from X-ray free-electron-laser can form a nanoscale mm-long cavity in LiF. The laser-generated shock pressure results in channel formation with >1,000 length-to-diameter aspect ratio. The development of void is analyzed via continuum and atomistic simulations revealing a sequence of processes leading to the final long cavity structure. This work presents the study of mm-long nanochannel formation by a single high-brilliance X-ray free-electron laser pulse. With MHz repetition rate X-ray free electron laser opens a new avenue for the development of lab-on-chip applications in any material, including those non-transparent to optical lasers. A single ultrashort pulse from X-ray free-electron laser is shown to produce a submicron, with >1,000 length-to-diameter aspect ratio long channel in solid material. The results open a new avenue for development of artificial nanofluidic devices with confinement down to the molecular level.

We can benefit from various services with context recognition using wearable sensors. In this study, we focus on the contexts acquired from sensor data in the nostrils. Nostrils can provide various contexts on breathing, nasal congestion, and higher level contexts including psychological and health states. In this paper, we propose a context recognition method using the information in the nostril. We develop a system to acquire the temperature in the nostrils using small temperature sensors connected to glasses. As a result of the evaluations, the proposed system can detect breathing correctly, workload at an accuracy of 96.4%, six behaviors at an accuracy of 54%, and eight behaviors in daily life at an accuracy of 86%. Moreover, the proposed system can detect nasal congestion, therefore, it can log nasal cycles that are considered to have a relationship with the autonomic nerves and/or biological states.

Over the past century, understanding the nature of shock compression of condensed matter has been a major topic. About 20 years ago, a femtosecond laser emerged as a new shock-driver. Unlike conventional shock waves, a femtosecond laser-driven shock wave creates unique microstructures in materials. Therefore, the properties of this shock wave may be different from those of conventional shock waves. However, the lattice behaviour under femtosecond laser-driven shock compression has never been elucidated. Here we report the ultrafast lattice behaviour in iron shocked by direct irradiation of a femtosecond laser pulse, diagnosed using X-ray free electron laser diffraction. We found that the initial compression state caused by the femtosecond laser-driven shock wave is the same as that caused by conventional shock waves. We also found, for the first time experimentally, the temporal deviation of peaks of stress and strain waves predicted theoretically. Furthermore, the existence of a plastic wave peak between the stress and strain wave peaks is a new finding that has not been predicted even theoretically. Our findings will open up new avenues for designing novel materials that combine strength and toughness in a trade-off relationship.

Investigation of the iron phase diagram under high pressure and temperature is crucial for the determination of the composition of the cores of rocky planets and for better understanding the generation of planetary magnetic fields. Here we present X-ray diffraction results from laser-driven shock-compressed single-crystal and polycrystalline iron, indicating the presence of solid hexagonal close-packed iron up to pressure of at least 170 GPa along the principal Hugoniot, corresponding to a temperature of 4,150 K. This is confirmed by the agreement between the pressure obtained from the measurement of the iron volume in the sample and the inferred shock strength from velocimetry deductions. Results presented in this study are of the first importance regarding pure Fe phase diagram probed under dynamic compression and can be applied to study conditions that are relevant to Earth and super-Earth cores.

Here, we report, that by means of direct irradiation of lithium fluoride a (LiF) crystal, in situ 3D visualization of the SACLA XFEL focused beam profile along the propagation direction is realized, including propagation inside photoluminescence solid matter. High sensitivity and large dynamic range of the LiF crystal detector allowed measurements of the intensity distribution of the beam at distances far from the best focus as well as near the best focus and evaluation of XFEL source size and beam quality factor M 2 . Our measurements also support the theoretical prediction that for X-ray photons with energies ~10 keV the radius of the generated photoelectron cloud within the LiF crystal reaches about 600 nm before thermalization. The proposed method has a spatial resolution ~ 0.4–2.0 μm for photons with energies 6–14 keV and potentially could be used in a single shot mode for optimization of different focusing systems developed at XFEL and synchrotron facilities.