Center Director: Fumihiko Kaminari (Professor, Faculty of Science and Technology)
Main Campus: Yagami
Center Overview
At Keio University, under the MEXT budget, we have formed a collaborative research hub with the University of Tokyo, RIKEN, the University of Electro-Communications, and the Tokyo Institute of Technology as part of the Alliance for Advanced Photon Science and Technology (Advanced Photon-Wave Control and Utilization Technology). We are primarily responsible for (i) promoting R&D cooperation and utilization research for photon ring facilities and (ii) materials science for the realization of high-intensity lasers, while also conducting research on themes that have been ongoing since the project's inception.
Specific topics include:
Development of ultra-broadband vector-shaped laser pulses for the formation of spatiotemporally controlled plasmonic reaction fields
Elucidation of nanoscale crystal structure dynamics and its application to nano-imaging measurements
Fusion research of frequency comb light sources and photon-wave control technology
Blue semiconductor laser-pumped Pr:ZBLAN fiber laser and its mode-locked oscillation
Development of femtosecond photon-wave control technology
Development of a mode-locked light source using four-wave mixing in a toroidal optical resonator
Development of precision polarization measurement of terahertz electromagnetic waves and its application technology
Fabrication of nitrogen-vacancy centers in diamond and their application to nano-light sources and nano-sensors.
Keywords and Main Research Themes
Ultrafast optical science, Laser engineering, Near-field optics, Nano-reaction field science
FY2017 Business Plan
■ Ongoing Activities from the Previous Fiscal Year: Background, Rationale, and Goals
As the project budget from MEXT is expected to be granted for FY2017, we will continue to advance research on themes 01 to 08 from FY2016, with the aim of developing new light source technologies and their applications. All of these research themes are being pursued with the goal of completion by the end of FY2017.
Additionally, we will continue to host seminars and symposiums to disseminate optical science and technology and foster human resources.
■ New Activity Goals and Content for FY2017, and Implementation Background
This marks the 10th year of continuous research since the center was established with funding from MEXT. In response to the new research goals for the collaborative hub established in 2012, as listed below, we have reviewed our research content to align with these goals and will concentrate our research resources particularly on light source development.
Developing fundamental technologies for the realization and dissemination of international frequency standards through complete frequency control
Development and utilization of coherent light sources from X-ray to terahertz regions through complete control of ultrashort light pulses
Generation and utilization of ultra-high-intensity light through complete control of broadband optical amplification
In line with this research content, the following themes will be implemented in the final fiscal year.
Formation of spatial correlations in local computing/memory elements using phase-change materials and the emergence of computing functions
New broadband and narrow-linewidth infrared spectroscopy
Development of energy-saving optical frequency comb light sources using micro-optical resonators
Fusion of photonic crystal engineering with silicon photonics
Generation of large-scale cluster states by controlling inter-mode quantum correlations of a frequency comb
Imaging of non-repetitive phenomena using the ultrafast burst imaging method
Development of visible-range double-clad fiber lasers and visible-range oxide laser media
Development of precision polarization measurement of terahertz electromagnetic waves and its application technology
Fabrication of nitrogen-vacancy centers in diamond and their application to nano-light sources and nano-sensors
In addition to the budget for hub formation, we are developing the results of our past photon-wave control research into innovative deep-ultraviolet laser technology. We are also advancing discussions to establish research that applies nanophotonics to the complex systems physics of materials and research to optically realize quantum simulators, and we will engage in activities to acquire funding as needed.
FY2017 Business Report
■ Implementation Details, Research Results, and Degree of Achievement against the Business Plan for the Fiscal Year
We successfully focused and propagated femtosecond plasmon pulses with wavelengths of 400 nm and 800 nm onto the tip of an aluminum tapered chip with a diameter of approximately 35 nm. Using Raman-resonant four-wave mixing, we succeeded in vibrational mode-selective coherent anti-Stokes Raman scattering imaging of graphene and carbon nanotubes. Furthermore, we created nanographene by reducing graphene oxide using this plasmon focusing method.
We experimentally confirmed the change in the optical spectrum (spectrum of resonant modes) corresponding to the matching between the 2D pattern written on a phase-change material and the electric field distribution of the cavity mode, thereby demonstrating the coding of 2D information into a 1D spectrum.
We performed sub-Doppler resolution spectroscopy of phosphine molecules using a mid-infrared difference frequency generation source controlled by a frequency comb.
By increasing the blue semiconductor laser pump power to 20 W, we investigated the scalability of the visible-range laser output and the effects of thermal load. Since the use of Pr3+, Mg2+:SrAl12O19, Pr3+:YAP, and Pr3+:YAG, which have excellent thermal properties, is essential for utilizing even higher-power blue semiconductor lasers for pumping in the future, we fabricated ceramics, which is unprecedented for visible lasers. We confirmed that the former two materials could be oriented and sintered by applying a magnetic field to the slurry state before sintering. We grew the crystals and measured their emission characteristics. We also developed a strong magnetic field application device to fabricate these biaxial crystals as ceramic materials. Additionally, we investigated the properties of Co:MALO crystals, which can be used as a saturable absorber for passive Q-switching even at green wavelengths, and achieved passive Q-switching and intracavity SHG in the green for the first time.
We introduced an optical system capable of extending a device that can perform 25-frame ultrafast imaging measurements in a single pulse to a sub-nanosecond time window, and confirmed the generation of a laser ablation plume in a single shot. We also constructed a THz generation device and developed an experimental system capable of measuring a hyperspectral image of THz waves in a single pulse.
By appropriately designing the structural dispersion of a micro-optical resonator, we achieved anomalous dispersion and obtained mode-locked, ultrafast repetitive pulsed light. Furthermore, while coupling microresonators causes the resonant wavelength to mode-split, we precisely controlled the mode-split width to match the Brillouin gain frequency, thereby realizing a Brillouin laser.
We expanded the development of internal strain inspection technology for rubber materials using terahertz polarization measurement, enabling 2D imaging inspection.
Aiming to realize high-performance nano-light sources and nano-sensors using nitrogen-vacancy centers in diamond, we proceeded with optimizing the conditions for substrate microfabrication and nitrogen-doped chemical vapor deposition that we have been conducting, and made improvements to further increase the brightness and sensitivity of the nitrogen-vacancy centers.
■ Number of Published Papers (with number and major journal names), Number of Conference Presentations (domestic/international), and Social Contribution Achievements such as Events (date, location)
Number of published papers: 31 (in journals such as Appl. Phys. Express, Applied Physics Letters, Optics Express, Applied Optics, Sci. Report, etc.)
Number of conference presentations (64 domestic, 92 international)
Center-hosted seminars and symposiums (1 event): The 38th Alliance for Advanced Photon Science and Technology Seminar, "New Optical Science through Photon-Wave Control Challenged by Keio University," March 2, 2018, Raiosha, Keio University
■ Special Achievements through Center Activities
This center serves as the organizational body for Keio University's participation as a collaborative hub in MEXT's project for the formation of optical science hubs. It has contributed not only by promoting research projects through collaborative research among its members but also by advancing initiatives to disseminate optical science and technology by hosting symposiums. Furthermore, we collaborated on applications to acquire funding for the next term, which led to our selection for the FY2017 JST CREST research program (a five-year project). We are also proceeding with considerations to apply in collaboration with the University of Tokyo for the MEXT Q-LEAP program starting in FY2018.
Project Members
Principal Investigator
Fumihiko Kaminari
ProfessorDepartment of Electronics and Electrical Engineering, Faculty of Science and TechnologyKotaro Oka
ProfessorDepartment of Biosciences and Informatics, Faculty of Science and Technology