• 　Using laser fabrication, we are developing techniques to enhance material surface properties and functionality. For example, to create a functional interface, we aim to clarify, by way of simulation and experimentation, the phenomenon that occurs when the surface of a material is irradiated using a laser beam.
• 　We expect that the results of our research will be widely applicable, including biomedical devices.
• ■　Creation of biocompatible surfaces
• 　Materials used for artificial organs, vessels, and other bio-implants require excellent tissue and cell biocompatibility. Therefore, we are exploring the creation of biocompatible surfaces using a new laser irradiation process in this study.
• 　We have succeeded in imparting a biologically active function to titanium-based materials by applying the laser irradiation technique. When such a material that has a biologically active function is inserted in a living body, hydroxyapatite (the principal constituent of bones and teeth) precipitates on the surface. Using the laser irradiation technique, we can manufacture bone-adherent implants, and we envisage their application to artificial joints or dental implants.
• 　This research aims to discover such breakthrough solutions for biomedical applications using the laser irradiation technique.

• On the basis of optical engineering, optical technologies for sensing mechanical motion, spectroscopic properties, and other physical/chemical characteristics are investigated. Moreover, using semiconductor micro/nano-fabrication technology, integrated micro-optical sensors, micro/nano optical systems, optical micro-electro-mechanical systems (MEMS) are studied. Micro laser scanner for display, deformable mirror for telescope, optical displacement encoder, and fluorescent analysis system are the examples of research topics.

Optical design, Optical industries, Industries relating to semiconductor micro fabrication and MEMS, optical telecommunications, etc.

• Nakagawa group has dedicated to pursue scientific principles for molecular control of interface function occurring at polymer/other material interfaces and to put them into practice in nanoimprint lithography promising as a next generation nanofabrication tool. We are developing advanced photo-functional materials such as sticking molecular layers for "fix by light", UV-curable resins and antisticking molecular layers for "preparation by light", fluorescent resist materials for "inspection by light", and hybrid optical materials "available to light" and new research tools such as mechanical measurement systems to evaluate release property of UV-curable resins.

Our research aims at creating new devices to control photon, electron, and magnetism.

• 1. Development of Distributed Feedback (DFB) Laser Diodes (LD) widely used in optical communications systems realizing a highly information-based society. This LD increases the transmission capacity by 25,000 times per fiber which means the bit rate of 10Tb/s.
• 2. Nitride semiconductors famous for blue light emitting diodes.
• (a) Proposal of InGaAlN system considering device applications in 1989
• (b) Success in growth of single crystalline InGaN by metalorganic vapor phase epitaxy (MOVPE) in 1989
• (c) Prediction of band-gap energy (Eg) of InN much smaller than the values reported in 1980s and its 　 experimental confirmation in 2002
• (d) Observation of photoluminescence from InGaN in 1991
• (e) Prediction of phase separation in InGaAlN in 1997

DFB-LD: Fabrication of periodic structure with submicron scale, Epitaxial growth of semiconductor films on the substrate with fine structures, LD fabrication process, device evaluation, and device simulation

Nitride Semiconductors: MOVPE growth, N-polar growth, Evaluation of semiconductor materials, Fabrication of light-emitting devices, solar cells, and high-power transistors