Since the author published laser ceramics in 1995, various translucent ceramics have been researched and developed worldwide. High-quality single crystals are used as laser gain materials because of their low scattering and excellent uniformity, resulting in efficient laser oscillation and superior beam quality. In contrast, low-quality transparent ceramics have been impacted by various scattering sources, such as residual pores and inclusions, which must be eliminated to improve their quality. Additionally, it is essential to produce a laser gain medium with an extremely uniform distribution of refractive index and without birefringence. Achieving these requirements demands highly advanced processing technology. However, this approach alone does not completely resolve the issue, as there is still a significant challenge to overcome. According to Rayleighs scattering theory, grain boundaries—atomic-level defects characterized by numerous dislocations—act as sources of scattering. Therefore, it is important to investigate the fundamental nature of these grain boundaries.
In contrast, the optical quality of single crystals currently in practical use has faced challenges. Issues such as inhomogeneous regions, including cores and growth striations within the center of the ingot, indicate that the optical quality is not perfect. A crucial first step in addressing this issue is to overcome the limitations of ceramics and achieve properties that are equal to or superior to those of existing single crystals.
Ceramics are gaining attention in research and development for their capability to synthesize composites with complex structures that traditional single-crystal techniques cant produce. In laser technology, ceramics have shown impressive functions and output power. For example, newly discovered ceramic materials with high Verdet constants are now being utilized in Faraday rotators for high-output applications. Additionally, advancements have led to improved optical transmission in the short wavelength range, surpassing single crystals. Thus, ceramics are becoming a leading paradigm in optics.

Akio Ikesue was born in Japan in 1958. He received his B.E., M.E., and Dr. Eng. degrees in Materials Science and Technology from Nagaoka University of Technology, Japan, in 1981, 1983 and 1996, respectively. He worked as a research scientist at Kurosaki Refractory Co., FANUC Co., and Japan Fine Ceramics Center (1999-2005). Now he is chief officer of World Lab. Co. (Nagoya, Japan). He also held the positions of an executive scientist at SCHOTT AG (Mainz, Germany), and invited professor at Pierre and Marie Curie University (Paris 6, Paris France), guest professor in SICCAS (Shanghai Institute of Ceramics) and PIFI fellow in CAS (Chinese Academy of Science). In 1995, he succeeded in fabricating the optical grade polycrystalline neodymium (Nd)-doped Yttrium Aluminum Garnet (YAG) ceramic for the first time in the world, and pioneered the high efficiency laser generation using polycrystalline ceramics. He is the recipient of numerous awards including Progress Award from laser society of Japan in 2001, 2005, Technical Promote Award of Japan Ceramic Association in 2002, Fulrath Award from the American Ceramic Society in 2003 and Photonics and Quantum Electronics Award from the Applied Physics Society of Japan in 2007. Otto-Schott Research Award from Ernst-Abbe Funds in 2008, and fellow from American Ceramic Society in 2009, Kato Memorial Award in 2022 and Okura Award in 2024. He is author of more than 100 technical publications.