University of Electro-Communications, Institute for Laser Science, Tokurakawa Lab
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
The key words: "fiber laser in-band pumping", "Kerr-lens mode-locking" and "Tm doped Sesquioxide crystal"
Tm doped Sesquioxide has many interesting superior properties, e.g.
1. They show large emission cross section above 2000 nm where less H2O absorption exists.
2. They posses large Stark splitting effect and can operation in quasi 4-level laser mode at room temperature.
3. They have superior thermal and mechanical properties.
These properties would allow high power ultra short pulse operation at the wavelength range of 2 um.
In combination with fiber laser in-band pumping, we have succeeded in the first Kerr-lens mode locked Tm doped solid state laser with the highest peak intensity in the world.
Now we are aiming further power scaling where standard 1 μm or 0.8 μm based nonliner optical converson can not reach.
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.
