Ultrafast optical probing is a widely used method of underdense plasma diagnostic. In relativistic plasma, the motion blur limits spatial resolution in the direction of motion. For many high-power lasers the initial pulse duration of 30–50 fs results in a 10–15 μm motion blur, which can be reduced by probe pulse post-compression. Here we used the compression after compressor approach [Phys.-Usp. 62, 1096 (2019); JINST 17 P07035 (2022)], where spectral broadening is performed in thin optical plates and is followed by reflections from negative-dispersion mirrors. Our initially low-intensity probe beam was down-collimated for a more efficient spectral broadening and higher probe-to-self-emission intensity ratio. The setup is compact, fits in a vacuum chamber and can be implemented within a short experimental time slot. We proved that the compressed pulse retained the high quality necessary for plasma probing.

Tight focusing with very small f-numbers is necessary to achieve the highest at-focus irradiances. However, tight focusing imposes strong demands on precise target positioning in-focus to achieve the highest on-target irradiance. We describe several near-infrared, visible, ultraviolet and soft and hard X-ray diagnostics employed in a ∼1022 W/cm2 laser–plasma experiment. We used nearly 10 J total energy femtosecond laser pulses focused into an approximately 1.3-μm focal spot on 5–20 μm thick stainless-steel targets. We discuss the applicability of these diagnostics to determine the best in-focus target position with approximately 5 μm accuracy (i.e., around half of the short Rayleigh length) and show that several diagnostics (in particular, 3$\omega$ reflection and on-axis hard X-rays) can ensure this accuracy. We demonstrated target positioning within several micrometers from the focus, ensuring over 80% of the ideal peak laser intensity on-target. Our approach is relatively fast (it requires 10–20 laser shots) and does not rely on the coincidence of low-power and high-power focal planes.

In this work, we present experimental results on the behavior of liquid water at megabar pressure. The experiment was performed using the HIPER (High-Intensity Plasma Experimental Research) laser facility, a uniaxial irradiation chamber of GEKKO XII (GXII) at the Institute of Laser Engineering (ILE), and the PHELIX at GSI (GSI Helmholtz Centre for Heavy Ion Research), a single-beam high-power laser facility, to launch a planar shock into solid multilayered water samples. Equation-of-state data of water (H2O are obtained in the pressure range 0.50–4.6 Mbar by tuning the laser-drive parameters. The Hugoniot parameters (pressure, density, etc.) and the shock temperature were simultaneously determined by using VISAR and SOP as diagnostic tools and quartz as the standard material for impedance mismatch experiments. Finally, our experimental results are compared with hydrodynamic simulations tested with different equations of state, showing good compatibility with tabulated SESAME tables for water.

Molybdenum disulfide (MoS2) is expected to be applied for devices in various fields owing to its unique characteristics. Establishing a high-productivity manufacturing method which yields high quality films is an important and unresolved issue for the practical applications of MoS2. Among different techniques conducted by researchers all over the world, our approach is cold-wall metal-organic chemical vapor deposition, and we previously reported the deposition of MoS2 with i-Pr2DADMo(CO)3, a novel Mo precursor [S. Ishihara, et al., MRS Advances 3, 379-384 (2018).]. In this study, with the aim of further improving the quality of the MoS2 film using this new Mo precursor, various film formation conditions were controlled and the influence on the film quality was investigated. X-ray photoelectron spectroscopy, atomic force microscopy and Raman spectroscopy were used as evaluation techniques of the samples. As a result, mm-scale uniform film was formed with the deposition time less than 30 min. at temperature as low as 400 °C to 500 °C. It was revealed that maintaining low Mo/S supply ratio (SRMo/S) is crucial in fabricating high quality films.

We report the investigation on the properties of a novel Te precursor (i-C3H7)2Te and its effectiveness in fabricating MoTe2. The vapor pressure of the precursor was obtained by measuring the pressure as a function of its temperature in a sealed chamber. As a result it showed a high vapor pressure of 552.1 Pa at room temperature. The decomposition of the precursor was also investigated using DFT calculation. It was shown that the most likely reaction during the course of the decomposition of (i-C3H7)2Te is (i-C3H7)2Te → H2Te + 2 C3H7. The effectiveness of the precursor on the fabrication of MoTe2 was also investigated. Sputter-deposited MoO3 was tellurized in a quartz-tube furnace at the temperature up to 440°C. The resulting film showed that the 80% of the original MoO3 was tellurized to form MoTe2. It was also shown that further optimization of tellurization is required in order to prevent formation of metal Mo and elemental Te.

We report the synthesis of MoS2(1-x)Te2x by co-sputtering deposition and effect of mixture on its bandgap. The deposition was carried out at room temperature, and the sputtering power on individual MoS2 and MoTe2 targets were varied to obtain films with different compositions. Investigation with X-ray photoelectron spectroscopy confirmed the formation of Mo-Te and Mo-S bonds after post-deposition annealing (PDA), and one of the samples exhibited composition ratio of Mo:S:Te = 1:1.2:0.8 and 1:1.9:0.1 achieving 1:2 ratio of metal to chalcogen. Bandgap of MoS1.2Te0.8 and MoS1.9Te0.1 was evaluated with Tauc plot analysis from the extinction coefficient obtained by spectroscopic ellipsometry measurements. The obtained bandgaps were 1.0 eV and 1.3 eV. The resulting bandgap was lower than that of bulk MoS2 and higher than that of bulk MoTe2 suggesting mixture of both materials was achieved by co-sputtering.

Molybdenum disulfide (MoS2) thin films were fabricated by two-step chemical vapor deposition (CVD) using (t-C4H9)2S2 and the effects of temperature, gas flow rate, and atmosphere on the formation were investigated in order to achieve high-speed low-temperature MoS2 film formation. From the results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) investigations, it was confirmed that c-axis orientation of the pre-deposited Mo film has a significant involvement in the crystal orientation after the reaction low temperature sulfurization annealing and we successfully obtained 3 nm c-axis oriented MoS2 thin film. From the S/Mo ratios in the films, it was revealed that the sulfurization reaction proceeds faster with increase in the sulfurization temperature and the gas flow rate. Moreover, the sulfurization under the H2 atmosphere promotes decomposition reaction of (t-C4H9)2S2, which were confirmed by XPS and density functional theory (DFT) simulation.

In 1988, a very powerful and versatile coudé echelle spectrograph was installed at the Anglo-Australian Telescope. Since then it has been winning about 30% of AAT time and has been highly productive scientifically. Therefore, using a coudé auxiliary telescope (CAT) to give the spectrograph more use and to free the AAT for other work is a very attractive possibility, particularly if the CAT can give a sensitivity similar to that obtained with the 3.9-metre telescope. While a conventional CAT with such performance would be very expensive, a much cheaper instrument should approach this goal, at least for high resolution spectroscopy. Even so, the cost could not be met in a reasonable time within the AAO’s budget; hence, additional international collaboration is being sought.

Molybdenum disulfide (MoS2), one of the transition-metal dichalcogenides, is a 2-dimensional semiconducting material that has a layered structure. Owing to excellent optical and electronic properties, the ultra-thin MoS2 film is expected to be used for various devices, such as transistors and flexible displays. In this study, we investigated the physical and chemical properties of sputtered-MoS2 film in the sub-10-nm region by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). As the results of Raman spectroscopy investigations, we observed two Raman modes, E12g and A1g, in the 2-dimensional MoS2 films. As the thickness of the MoS2 film decreased, the peak frequency difference between E12g and A1g modes increased. From the XPS investigations, we confirmed sulfur reductions from the 2-dimensional MoS2 films. Therefore, we considered that the sulfur vacancies in the MoS2 film affected the Raman peak positions. Moreover, we performed the additional sulfurization of sputtered-MoS2 films. From the XPS and Raman investigations, the quality of the sputtered-MoS2 films was improved by the additional sulfurization.

To increase X-ray photon number generated by laser-cluster interaction, it is important to understand the dependence of X-ray generation on cluster size. We carried out Xe K-shell X-ray generation using a conical nozzle with Xe clusters, the radius of which was controllable by adjusting the backing pressure. The experiment clarifies the result that the Xe K-shell X-ray photon number increases with increasing cluster radius from 8 to 12 nm, and saturates at the radius between 12 and 17 nm. We also investigated the Xe K-shell X-ray photon number dependence on laser intensity, and found that the threshold laser intensity of the Xe K-shell X-ray generation exists between 2 × 1017 and 5 × 1018 W/cm2.

Changes in critical current properties depending on growth temperature (Ts) were clarified for Ba-Nb-O-doped YBa2Cu3Oy (Y123) films deposited by YAG- and excimer-PLD. Due to the introduction of Ba-Nb-O-nanorods, a vortex-Bose-glass-like behavior emerged as irreversibility lines and in-field critical current densities (Jcs) were improved. Crossover magnetic fields (Bcr) and in-field Jcs increased with the increase in Ts for the Y123 films with nanorods. These Ts-dependent critical current properties were attributable to the changes in morphology of the nanorods with Ts and were independent of laser source in PLD apparatuses. For the fabrication of RE123 coated conductors containing nanorods, optimization of Ts with taking both materials of RE123 matrix and nanorod into account is necessary to achieve higher in-field Jc.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

A Flood disaster struck the Islamic Republic of Pakistan in July 2010. It affected 3 million people and caused 1,400 deaths. Humanitarian Medical Assistance (HuMA) is a non-profit organization in Japan. The organization dispatched three personnel to Islamabad on 20 August in order to conduct an initial needs assessment. They discovered that medical assistance and supplies could not reach all of the victims, especially in the North. Their visits to the surrounding regions highlighted the Nowshera district of KPK province, which had not received enough assistance from the government or aid organizations despite the fact that there were thousands of Internally Displaced Persons (IDPs) with health issues such as diarrhea, eye and skin disease, and upper respiratory tract infection (URTI). On 03 September, the HuMA Disaster Relief Mission began with the purpose of providing medical treatment and promoting public health for the flood victims in the Nowshera District. Eleven medical providers and coordinators from HuMA operated field mobile clinics in the district in collaboration with a local counterpart non-governmental organization, Nippa Welfare Association (NWA). This project was supported financially by the grant funding from Japan Platform. Humanitarian Medical Assistance served seven sites in Nowshera Districts as mobile field clinics, and consulted 2,216 patients. Total distribution of disease was: (1) URTI = 18.1%; (2) skin disease = 17.9%; (3) musculoskeletal = 15.2%; and (4) others = 19.7%. The team considered continuous medical consultation in the Nowshera District after 2010. The HuMa medical activities ended at the end of September, and the organization donated multi-vitamin tablets, syrups, FE tablets, and anti-biotic cream in order to assist NWA's continuing assistance for the affected communities. The medical providers also left lists of medicines for local doctors and medical staff. Humanitarian Medical Assistance also provided basic supplies needed to prevent victims from experiencing further sanitation problems.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006