Refine your search:     
Report No.
 - 
Search Results: Records 1-8 displayed on this page of 8
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Multi-millijoule, diode-pumped, cryogenically-cooled Yb:KY(WO$$_{4}$$)$$_{2}$$ chirped-pulse regenerative amplifier

Ogawa, Kanade; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

Optics Express (Internet), 15(14), p.8598 - 8602, 2007/07

 Times Cited Count:21 Percentile:70.17(Optics)

Ytterbium (Yb$$^{3+}$$) doped gain media are one of promising laser materials for the next generation of diode-pumped high-power lasers. Yb-doped media have several advantages. It has wide absorption bandwidth, the low quantum defect, and the simple electronic structure. Yb:KY(WO$$_{4}$$)$$_{2}$$ (Yb:KYW) and Yb:KG(WO$$_{4}$$)$$_{2}$$ (Yb:KGW) have a large absorption and wide emission cross section, broad emission spectral range, and high thermal conductivity, yielding a high repetition-rate, high-energy, sub-picosecond pulses. However, multi-millijoule-class Yb:KYW or Yb:KGW lasers have not yet been reported so far, excepting a massive, joule-class Ti:sapphire laser pumped Yb:KGW regenerative amplifier. So, We developed a compact diode-pumped, cryogenically-cooled chirped-pulse Yb:KYW regenerative amplifier. An amplified pulse with an energy of 5.5 mJ and a high optical conversion efficiency of $$sim$$14% is achieved. Regenerative pulse shaping is also used to counter gain narrowing during amplification.

Journal Articles

High-energy, diode-pumped, picosecond Yb:YAG chirped-pulse regenerative amplifier for pumping optical parametric chirped-pulse amplification

Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

Optics Letters, 32(13), p.1899 - 1901, 2007/07

 Times Cited Count:38 Percentile:84.44(Optics)

A diode-pumped, cryogenic-cooled Yb:YAG regenerative amplifier utilizing gain-narrowing has been developed. A 1.2-ns chirped-seed pulse was amplified and compressed in the regenerative amplifier, simultaneously, which generated a 35-ps pulse with $$sim$$8-mJ of energy without a pulse compressor. Second-harmonics of the amplified pulse was used to pump picosecond two-color optical parametric amplification.

Oral presentation

Ultrabroadband optical parametric chirped-pulse amplification system, 2; Cryogenically-cooled Yb-doped solid-state CPA pump laser

Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

no journal, , 

no abstracts in English

Oral presentation

High-energy, cryogenic-cooled Yb:YAG chirped-pulse regenerative amplifier as an efficient picosecond OPCPA pump source

Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

no journal, , 

A diode-pumped Yb:YAG regenerative amplifier utilizing gain-narrowing has been developed. A chirped-seed pulse was amplified and compressed in the regenerative amplifier, simultaneously, which generated the picosecond pulses with 8 mJ of energy without a pulse compressor.

Oral presentation

Multi-millijoule pulse amplification in a diode-pumped Yb:KY(WO$$_{4}$$)$$_{2}$$ chirped-pulse regenerative amplifier

Aoyama, Makoto; Ogawa, Kanade; Akahane, Yutaka; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

no journal, , 

no abstracts in English

Oral presentation

High-energy, diode-pumped, picosecond Yb:YAG chirped-pulse regenerative amplifier as a pump source for optical parametric chirped-pulse amplification

Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

no journal, , 

We have developed a narrowband Yb:YAG chirped-pulse regenerative amplifier using gain-narrowing, which is suitable for direct OPCPA pumping without pulse compression. A chirped-seed pulse was amplified and compressed in the regen, simultaneously, which generated the picosecond pulses with 7.5-mJ of energy without a pulse compressor. In the experiment, output pulse from a mode-locked oscillator was split into two beams, which were used as seed pulses for both Yb:YAG regen and OPCPA. The seed pulse for the regen was positively chirped to 1.2 ns by a PANDA fiber before amplification. An Yb:YAG was cooled by a liquid-nitrogen cryostat and fiber-coupled laser diode was used to pump the regen. A gain narrowed amplified bandwidth (from 17 nm to 0.5 nm) corresponded to 35 ps (FWHM) duration. We also performed a parametric amplification by using the frequency-doubled, 25-ps pump pulse. We have observed OPA spectra at 850 and 1200 nm, simultaneously, with the maximum OPA gain of 10$$^{4}$$.

Oral presentation

High-energy, cryogenic-cooled Yb:YAG chirped-pulse regenerative amplifier as a pump source for picosecond optical parametric chirped-pulse amplification

Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi

no journal, , 

We have developed a diode-pumped, cryogenic-cooled Yb:YAG regenerative amplifier employing gain-narrowing. In the regenerative amplifier, a seed chirped-pulse was not only amplified but also temporally compressed, which generated the picosecond output pulses with 8-mJ of energy without a pulse compressor.

Oral presentation

Monoenergetic hard X-ray emission from carbon-nanotube-array coated targets with femtosecond laser pulses

Okano, Yasuaki*; Nishikino, Masaharu; Nakahara, Shogo*; Tokita, Shigeki*; Masuno, Shinichiro*; Hashida, Masaki*; Sakabe, Shuji*; Nakano, Hidetoshi*; Kawachi, Tetsuya; Nishimura, Hiroaki*; et al.

no journal, , 

The generation of monoenergetic hard X-rays more than 10 keV has attracted much attention for X-ray imaging in the field of high density physics and biomedical applications. Our group is currently developing an X-ray microbeam system to study radiobiological effects of cells as fundamental study of radiation therapy. In such applications, improvement of conversion efficiency (CE) from the driving laser to X-rays is an important issue and some approaches for efficient X-ray generation up to several keV have been proposed so far using low density, surface-structured targets, such as porous metals, velvet targets, and carbon nanotubes (CNTs), with the concepts of improvement of the laser absorption efficiency. In this work, we investigated the yields of K-alpha emission from bare and aligned CNT-array coated metal targets to take baseline data aiming to improve the CE in hard X-ray region (multi-keV to tens of keV) by adapting such kind of method.

8 (Records 1-8 displayed on this page)
  • 1