Taku Saiki

Bio: Taku Saiki is an academic researcher from Kansai University. The author has contributed to research in topics: Laser & Laser power scaling. The author has an hindex of 14, co-authored 67 publications receiving 595 citations. Previous affiliations of Taku Saiki include Osaka University.

Demonstrated fossil-fuel-free energy cycle using magnesium and laser

Abstract: The authors propose an energy cycle based on a renewable fuel. Magnesium is chosen as an energy carrier and is combusted with water to retrieve energy using many power devices. MgO, the combustion residue, is reduced back to Mg by laser radiation generated from solar and other renewable energy sources. They have achieved an energy recovery efficiency of 42.5% for converting MgO to magnesium, using a laser. Combined with a demonstrated 38% efficiency for converting an artificial sunlight source (metal halide lamp) into laser output energy indicates that the proposed energy cycle is already in a feasible range for practical use.

Total-reflection active-mirror laser with cryogenic Yb:YAG ceramics

Abstract: An efficient high-power laser operation has been demonstrated by using a cryogenic Yb:YAG composite ceramic with a total-reflection active-mirror arrangement. The composite ceramic, which had no high-reflection coating and was cooled with liquid nitrogen directly, showed four-level operation even at 67 kW/cm3 of high pump density. A 273 W cw output power was obtained with 65% optical efficiency and 72% slope efficiency.

Nd/Cr:YAG Ceramic Rod Laser Pumped Using Arc-Metal-Halide-Lamp

Abstract: We observed laser oscillations of rod-type Nd/Cr:YAG ceramics experimentally pumped using an arc-metal-halide lamp having a similar spectrum to solar light. An optical–optical conversion efficiency of 43% was obtained by chromium-ion codoping of Nd:YAG with an efficiency of 26%.

Petawatt and exawatt class lasers worldwide

Abstract: In the 2015 review paper 'Petawatt Class Lasers Worldwide' a comprehensive overview of the current status of highpower facilities of >200 TW was presented. This was largely based on facility specifications, with some description of their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification (CPA), which made these lasers possible, we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed. We are now in the era of multi-petawatt facilities coming online, with 100 PW lasers being proposed and even under construction. In addition to this there is a pull towards development of industrial and multidisciplinary applications, which demands much higher repetition rates, delivering high-average powers with higher efficiencies and the use of alternative wavelengths: mid-IR facilities. So apart from a comprehensive update of the current global status, we want to look at what technologies are to be deployed to get to these new regimes, and some of the critical issues facing their development.

Aluminum as energy carrier: Feasibility analysis and current technologies overview

Abstract: Aluminum is examined as energy storage and carrier. To provide the correct feasibility study the work includes the analysis of aluminum production process: from ore to metal. During this analysis the material and energy balances are considered. Total efficiency of aluminum-based energy storage is evaluated. Aluminum based energy generation technologies are reviewed. Technologies are categorized by aluminum oxidation method. Particularly, the work focuses on direct electrochemical (anodic) oxidation of aluminum, aluminum–water reaction in alkaline solution, mechanochemical activation of aluminum, mechanical activation of aluminum and high-temperature aluminum–water reaction. The objective is methods overview including technological principle, efficiency, urgent problems and possible application areas.

Materials development and potential applications of transparent ceramics: A review

Abstract: Transparent ceramics have various potential applications such as infrared (IR) windows/domes, lamp envelopes, opto-electric components/devices, composite armors, and screens for smartphones and they can be used as host materials for solid-state lasers. Transparent ceramics were initially developed to replace single crystals because of their simple processing route, variability in composition, high yield productivity, and shape control, among other factors. Optical transparency is one of the most important properties of transparent ceramics. In order to achieve transparency, ceramics must have highly symmetric crystal structures; therefore, the majority of the transparent ceramics have cubic structures, while tetragonal and hexagonal structures have also been reported in the open literature. Moreover, the optical transparency of ceramics is determined by their purity and density; the production of high-purity ceramics requires high-purity starting materials, and the production of high-density ceramics requires sophisticated sintering techniques and optimized sintering aids. Furthermore, specific mechanical properties are required for some applications, such as window materials and composite armor. This review aims to summarize recent progress in the fabrication and application of various transparent ceramics.