Laser machining is widely applied to manufacturing sites as a high-speed and non-contact machining method. The beam mode of the laser is divided into single mode and multimode. Although the single mode has good light condensing property and is suitable for fine machining, it has not been widely used in the machining field so far because it is difficult to increase the output and the cost of the oscillator is high. Although the multi-mode is inferior to the single mode in light condensing property, it is possible to increase the power, and is widely applied to laser beam machining. In recent years, low-cost, high-power single-mode lasers have been put on the market, and their application to the processing field has been advanced. In this paper, the history and features of the development of laser oscillators and laser beam machining technology applied to laser beam machining are explained with examples.

In this review, I will discuss what is required to improve photovoltaic parameters, such as short-circuit current density (J_SC), open-circuit voltage (V_OC), and fill factor (FF), in terms of photovoltaic conversion elementary processes. These elementary processes can be directly observed by time-resolved spectroscopic measurements. Thus, I will introduce the latest research topics, focusing on these spectroscopic analyses. Finally, I will also mention future prospects for further improvements in power conversion efficiency of polymer solar cells.

Toward the efficient electrochemical reactions, we are focusing on the utilization of strong coupling between matter and vacuum electromagnetic fields. We introduce the plasmonic control for the confinement of light energy for the exotic excitation. In addition, we also introduce the use of vibrational strong coupling for the modulation of properties of water.

Anisotropic self-assembled nanomaterials in transition metal compounds have attracted much attention because of rich physical properties and structural controllability. Although peculiar sample-preparation conditions and/or high-temperature processing are, in general, necessary to fabricate anisotropic nanostructures in oxides, nanometer-scale spinodal decomposition in spinel-type manganese oxides result in the highly-ordered nanostructures, by only simple heat treatment at relatively low temperatures. In this paper, we will introduce our recent studies on the formation of checkerboard and lamellar nanostructures consisting of Mn-rich tetragonal and Mn-poor cubic nanodomains in manganite spinel (Co,Mn,Fe)₃O₄ annealed at 375 ℃.

Material properties depend largely on the crystal structure dimensionalities and the associated electronic structures. If the crystal structure dimensionality can be switched reversibly in the same material, a giant property change may be controllable. In this review, we introduce the demonstration of a direct three-dimensional (3D) to 2D structural phase transition to switch electronic conductivity in (Pb_1-xSn_x)Se, a solid solution of 3D PbSe and 2D SnSe semiconductors. We induced the direct transition between 3D and 2D crystal structures in (Pb_1-xSn_x)Se epitaxial films by using a nonequilibrium growth technique. Reversible giant electronic property change was attained at x ～0.5 originating in the abrupt band structure switch from gapless Dirac-like state to semiconducting state. The present result would lead to further functional property switching in semiconductors.

Materials informatics is a fusion field of materials and information sciences, and has recently been attracting attention from both industry and academia because it has a potential to accelerate materials development beyond conventional materials science by incorporating developments in information science into materials science. In this article, we start by looking at materials informatics from the historical paradigm, and then describe the expectations and significance of Materials informatics. Then, we will show that recent topic showing that information technology does not solve a narrowly defined objective in materials science only, such as increasing simulation speed, but that concepts that have not existed in materials science up to now are being produced by integrating with information science.

This article is shown an insulator surface structural analysis. It is difficult for experiments because of the charging/discharging phenomena during electron or ion particles bombardments. We therefore show an experimental method using pulsed neutral beams for insulator surface analysis. Incident particles were 3 keV-⁴He⁰ or 3 keV-²⁰Ne⁰ beams and backscattered particles were detected by an MCP (micro channel plate). Then, a time-of-flight spectrum was obtained. This method is called low energy atom scattering spectroscopy. An example of low energy atom scattering spectroscopy is shown about MgO(111) crystal. This method is useful for the analysis of insulator surfaces as well as meta or semiconductor surfaces under electromagnetic field.