University of Electro-Communications, Institute for Laser Science
Main subjects of our lab is following. We are doing these research subject with domestic companies and university either in Japan or oversea.
High power highly effecienct mode-locked MId-IR solid state laser
Research at the Tokurakawa Laboratory
At the Tokurakawa Laboratory, we are dedicated to developing next-generation light sources.
Why do we develop light sources?
Laser light sources are a core technology that supports both industry and academia in Japan. However, most of these lasers are currently imported from overseas. The high cost of purchasing such systems poses a major challenge for researchers, and leads to a significant outflow of research funds abroad.
In some cases, due to patent restrictions or national security concerns, the latest laser systems cannot even be imported, limiting Japan’s ability to stay at the forefront of cutting-edge research. On the other hand, if we can develop and utilize advanced laser technologies that are not yet available on the market, we can produce results that give us a clear competitive advantage.
Our vision
We aim to develop compact, high-brightness tabletop light sources that cover a broad spectral range—from soft X-rays to the mid-infrared and terahertz regions. Light in these wavelength ranges is crucial for both scientific research and industrial applications.
In Japan, large-scale facilities such as SPring-8 and NanoTerasu, along with smaller synchrotron radiation facilities like AichSR, SAGALS, and HISOR, have been constructed nationwide in collaboration between industry and academia to provide access to such light.
However, each facility has its limitations in terms of cost, availability, brightness, and time resolution. A tabletop system capable of generating light in these spectral regions would offer significant advantages—making powerful research tools more accessible, flexible, and widely usable.
We are working toward making this vision a reality.
At the Tokurakawa Laboratory, we collaborate with both domestic and international companies and universities to develop novel light sources. In particular, we are focusing on the development and application of high-intensity, ultrashort-pulse laser sources in the 2 μm wavelength region.Currently, we are working on the following research themes:
Our Research ThemesAt the Tokurakawa Laboratory, we collaborate with both domestic and international companies and universities to develop novel light sources. In particular, we are focusing on the development and application of high-intensity, ultrashort-pulse laser sources in the 2 μm wavelength region. Currently, we are working on the following research themes:Tabletop high-brightness light sources spanning soft X-rays to mid-infrared and terahertz regions
1. 2.1 μm ultrashort-pulse Ho-doped solid-state laser oscillator
2. Low repetition rate (1–10 MHz)2.1 μm high-power Ho-doped solid-state amplifier
3. 50–100 W average power, 100 kHz–10 MHz repetition rate (DFC Ho:YAG)
4. 1.9 μm high-power Tm-doped fiber laser Hundreds of watts output, robust and low-cost design
5. Nonlinear pulse compression Highly efficient, multi-pass cavity configuration
6. 2 μm nanosecond-pulse Tm-doped fiber laser for materials processing ~100 ns pulse duration, 25 W output
7. Development of a holographic microscope Photothermal imaging using a custom-built mid-infrared light source
8. Development of a compact, high-repetition-rate mid-infrared dual-comb source Handheld size, based on Cr:ZnS
In the last decade, 2 μm fiber lasers have attracted huge attention due to its scalability of peak intensity (larger mode filed area and lower Raman gain, and higher self focusing limit... ). It could enable us overcome the limitation of well developed current 1 μm Yb fiber laser system. We are aiming to develop user friendly, compact, easy maintenance, fiber lasers.
We have succeeded in a development of tunable SESAM (or nonlinear loop mirror) mode-mode locked Tm fiber laser, All fiber amplifier system with above 10 W average power, soliton mode locked Tm fiber laser with nonlinear polarization rotation.
Now we are aiming further improvement of those light source and their applications such as super continuum generaton , material processing fo polymer and Silicon.
Mode-locked fiber laser at the wavelength range of 2μm
Amplifier spontenios emissioin light sourde /Super continuum generation / tunable source at Mid IR wavelength range
We are aiming to access 2-20 μm Mid-IR wavelength range by a nonlinear wavelength conversion with 2μm pump sources.
As applications, we are very interested in Mid-IR LIDAR which is important for global environmental monitoring/improvement.
We are also interested in Breath/Bread analysis for clinical diagnostic/screening of human disease.
Environmental monitoring and clinical diagnostic/screening are very important for us, the cost for environmental problem and health care in the world is rapidly increasing. Shortage of food water, electricity could be happen in our life so we need to invest new technology to overcome, mitigate those problems.
