This page is the Uno's research group in University of Yamanashi. We make noble gas lasers, investigate the characteristics of our lasers, and study laser processing and laser medicine by using our lasers. We make laser tubes, pulse power supplies and excitation circuits by ourselves. Keywords are gas laser, discharge, high voltage pulse power, UV laser, VUV laser, excimer laser, CO2 laser, laser engineering, optics, electrical circuit, electromagnetism, Quantum mechanics, laser processing, laser medicine, dentistry and etc. ●
Blog
Click the image to see our blog. Our blog shows our daily, trips for conferences, our study and etc. Language is Japanese.
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中文
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Work
We study longitudinally excited gas lasers and develop noble excimer lasers and CO2 lasers. We control the discharge, the laser pulse and the laser beam. In addition, we study laser processing of glass, polymer resin and composite material, and laser medicine of dentistry and dermatology, without heat effect like carbonization, cracks, melting and discoloration, by our handmade lasers. Click an image to see details.
Department of Electrical and Electronic Engineering,
Faculty of Engineering,
University of Yamanashi
Associate Proffesor, Dr. Kazuyuki Uno
kuno@yamanashi.ac.jp
Longitudinally excited gas laser
We study noble gas lasers. Gas lasers oscillate from mid-infrared region to vacuum ultraviolet region. Our objective is the development of a noble gas laser with a high laser energy, high quality beam, a high repetition rate, and a portable device. Therefore, we focus on a longitudinal excitation scheme with a low-gas-pressure (less than 10 kPa) discharge. In the longitudinal excitation, the oscillation of a CO2 laser (9〜11 μm), a F* laser (630〜780 nm), a XeF laser (351 nm), a N2 laser (337 nm), a KrF laser (248 nm) and a F2 laser (157 nm) and so on were observed.
We are developing a longitudinally excited UV gas laser with high quality beam and a simple device. We are trying the improvement of beam quality and gas lifetime, and the development of a UV gas laser with high performance like a solid-state laser and a smaller device than a UV solid-state laser.
We have developed a excimer-lamp-like N2 laser (337 nm), a slow-discharge pumped N2 laser with a risetime of discharge voltage of several tens μs, a high-quality beam N2 laser with a beam divergence of 0.3 mrad (full angle), a low-gas-pressure F2 laser (157 nm) with a gas pressure of 40 Torr, and etc.
Now our objectives are the development of a longitudinally excited KrF laser (248 nm), ArF laser (193 nm) and F2 laser with high quality beam and a high laser energy.
Furthermore we will try developing a rare-gas dimer laser such as Xe2* laser (172 nm), Kr2* laser (147 nm) and Ar2* laser (126 nm).
We are developing a longitudinally excited CO2 laser whose parameters including a laser pulse waveform, a laser beam profile, polarization and a wavelength can be controlled.
In the longitudinally excited CO2 laser, a long pulse with the width of several ms was general. But we realixed the oscillation of a short pulse with a spike pulse with a pulse width of 100 ns in 2009. Recently, our single CO2 laser produced a long pulse with a pulse width of 10 μs to 100 μs, a short pulse with a spike pulse width of 100 ns to 300 ns and a tail length of several μs to 200 μs, and a tail-free short pulse with a wodth of 100 ns to 300 ns by the control of a discharge.
Additionally, our single CO2 laser produced Gaussian beam, flat-top beam and doughnut beam by the control of the optical cavity. Our CO2 laser produced Gaussian beam with M2 = 1.
In the collaborative reseawrch with Prof. Endo in Tokai Univ., our CO2 laser produced random polarized beam, azimuth polarized beam and radial polarized beam.
In the collaborative reseawrch with Prof. Nakano in Kindai Univ., we aim to downsize the CO2 laser device.
In the collaborative reseawrch with Seidensha Electronics CO., LTD of Japan, we are working on commercialization of the CO2 laser device.
This work is supported by the JST A-STEP (2018.10. - 2022.03.).
We are investigating a suitable CO2 laser pulse for various materials by using our CO2 laser with the controllable laser pulse wavehorm.
The controll of a laser pulse waveform is important for CO2 laser processing because a processing mechanism and heat effect depend on a laser pulse shape and a pulse width. Heat may give thermal influence such as carbonization, charring, melting and cracks, and/or thermal effect to improve a processing efficiency. So, in CO2 laser processing, each material may have an optimal laser pulse waveform for good condition of an irradiated part and/or a processing efficiency.
Our current processing samples are glass such as SiO2, soda-lime glass and alkali-free glass, polymer resin such as PET, PI, PTFE and PC, and conposite materials such as CFRP and GFRP.
We study the drilling of hard tissue, the incision of soft tissue, and the repair and regeneration of hard tissue.
Now dentists have various types of lasers. CO2 lasers are used for the incision of soft tissue and hemostasis. When teeth are irradiated by dentist's CO2 laser, teeth carbonize.
In our CO2 laser, the tooth drilling without carbonization was realized. Moreover, our CO2 laser produced deep depth at a low fluence efficiently. We are investigating the effect by the laser pulse shape and the pulse width. Our objective is the development of a dental treatment device capable of drilling of hard tissue, incision of soft tissue and hemostasis by a single and portable CO2 laser.
In the collaborative reseawrch with Department of Dentistry & Oral Surgery, University of Yamanashi, we are studying the effect of CO2 laser in the implant therapy. In the implant therapy, the amount of alveolar bone supporting the teeth and the fixing speed of the implant are important. We research the characteristics of the repair and regeneration of bone depended on the laser pulse waveform and the total irradiated fluence of our CO2 laser.
This work was supported by the JSPS KAKENHI (2016.04. - 2019.03.).
2019.05.21-24. LAMP2019. International Conference Center Hiroshima, Hiroshima, Japan.
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2019.08.xx. Presentation of B4 students.
2019.09.04-06. The Institute of Electrical Engineerings of Japan, Society Conference of Electronics, Information and Systems. University of the Ryukyus, Okinawa, Japan.
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We publish research results every time in OPIC, LPM, Photonics Asia, Photonics West, the anual meeting of the Laser Society of Japan and the meeting of the Japan Society of Applied Physics. In our laboratory, students are also present at international conferences and domestic conferences. The state of presentation is described in the research achievement of our laboratory blog【Here. in Japanese】．
