Yusuke Ito

The extremely intense light emitted from femtosecond laser pulses enables micro-drilling of glass. However, there are problems in femtosecond laser drilling, including low drilling speed and the damage during drilling. Because the volume removed by one femtosecond laser pulse is too small, hundreds of pulses must be focused on a single spot to create a hole with a diameter of 10 μm and a depth of over 100 μm. Furthermore, strong stress waves generated during the processing cause damage around th

Amorphous oxide thin films in the pseudobinary system Li4SiO4-Li3PO4 and Li4GeO4-Li3PO4 were fabricated using pulsed laser deposition (PLD) with a KrF excimer laser. The ionic conductivities of obtained thin films were 10−8 to 10−6 S cm−1 at room temperature. Bulk-type all-solid-state batteries using LiCoO2 particles surface-modified with ortho-oxosalt thin films were constructed to assess the influence of oxide coatings on cell performances. Higher ion-conductive oxide thin films studied here a

Li-ion conduction in electrolyte materials and its intercalation properties in active materials are key factors that determine the electrochemical performances of batteries.

The development of femtosecond lasers has renovated micromachining technology, enabling the microdrilling of transparent materials at high speed. Although effective, this technique is still imperfect because irregular microscopic damage occurs during processing. Several factors in the formation of damage induced by a single laser pulse have been suggested; however, the entire mechanisms of damage formation in the process of drilling are not fully understood. Here we investigated the causes of mi

Although femtosecond lasers enable microfabrication of transparent materials, precise processing is difficult owing to the inevitable damage caused to the surroundings of the processed region. In the present work, we combine pump-probe imaging with a high-speed camera to capture the dynamics of pressure waves varying from pulse to pulse, before a desired shape is created by hundreds of pulses. The results demonstrate that the pressure waves change their forms and locations as the number of pulse

Highly ion-conductive thin films in the pseudobinary system Li4GeS4–Li3PS4 were prepared by pulsed laser deposition (PLD). Raman spectra showed that the obtained thin films were mainly composed of Li+, (PS4)3−, (GeS4)4− and (GeS1/2S3)3− ions. The 33Li4GeS4·67Li3PS4 (mol %) thin film showed glass transition phenomenon at about 160°C, suggesting that the obtained amorphous thin film was in a glassy state. The thin film exhibited higher ionic conductivity than the Li4GeS4 and Li3PS4 thin films beca

Precision machining of sintered zirconia ceramics is expected for various applications such as dental prostheses or artificial femoral heads. However, machining of zirconia is a major challenge because of its high hardness. We have found that the bending strength and fracture toughness of this material decrease with an increase in temperature. To use this characteristic, we propose a high-speed milling process with a cutting speed of more than 500 m/min because high-cutting speed can generate a

Precision machining of glass has been receiving attention in various applications because of the use of glass interposers in layered semiconductors or glass substrates for microfluidic chips. These applications require complicated and three-dimensional machining for further product functionality. Etching is conventionally used for precision machining of glass. However, applying etching for three-dimensional machining is difficult, and thus, a method which is applicable to three-dimensional machi

Sodium rechargeable batteries using earth-abundant raw material sources are more suitable for wide application as compared to lithium batteries. The development of inorganic solid electrolytes with high Na-ion conductivity is indispensable to realize all-solid-state sodium batteries. The sulfide solid electrolyte with cubic Na3PS4 phase has a high sodium-ion conductivity at room temperature. This research has addressed, for the first time, the preparation of Na3PS4 electrolyte thin films using p