http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nan Ei YU,Kenji Kitamura,Sunao Kurimura 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.4
A periodically poled device was investigated by using fourth-order quasi-phase-matched (QPM) second harmonic generation (SHG) in MgO-doped stoichiometric lithium tantalate (LiTaO3). The effective nonlinear coefficient was found be 2.4 pm/V by using fourth-order QPM SHG at the fundamental wavelength of 1064 nm. For first-order QPM SHG, the effective value of d33 could be 9.2 pm/V. Using the sensitive higher-order QPM SHG method, we investigated the relationship between the domain duty ratio and the conversion efficiency.
Group Velocity Matched Second Harmonic Generation in Periodically Poled Potassium Niobate
차명식,유난이,Sunao Kurimura,Kenji Kitamura,Satoshi Ashihara,Takayuki Ohta,Tsutomu Shimura,Kazuo Kuroda,Oc-Teob Jeon 부산대학교 유전체물성연구소 2004 유전체 논문집 Vol.3 No.
We investigated the group velocity matched second harmonic generarion in periodically poled potassium niobate. The QPM wavelength bandwidth was 38 nm around 1520 nm at 35℃ in 14.4㎛ QPM period with 10.5 mm interaction length. We also observed ultra-fast pulse used type-ⅠSHG conversion efficiency. The SHG conversion efficiency of the PPKN crystal was about 3 times that of type-Ⅰ SHG in PPMgLN.
Nonlinear Receding Horizon Control of a Tandem Cold Millin Acceleration and Deceleration Conditions
Kohei Ozaki,Toshiyuki Ohtsuka,Kenji Fujimoto,Akira Kitamura,Makishi Nakayama 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
For precise control of tension and thickness in a tandem cold millinac celeration and deceleration conditions, we employ an onlin ear model in cluding the rolling speed as a time-varying parameter. It is demon strated in simulation results that nonlinear receding horizon control by realtime optimization achieves satisfactory performance for the nonlinear model.
Fluoride single crystals for UV/VUV nonlinear optical applications
Shimamura Kiyoshi,Villora Encarnacion G.,Muramatsu Kenichi,Kitamura Kenji,Ichinose Noboru The Korea Association of Crystal Growth 2006 한국결정성장학회지 Vol.16 No.4
The growth characteristics and properties of large size $SrAlF_5$ single crystals are described and compared with those of $BaMgF_4$. Transmission spectra in the vacuum ultraviolet wavelength region indicate a high transparency of $SrAlF_5$ (about 90% without considering surface reflection loses) down to 150 nm, on contrast to the optical loses observed for $BaMgF_4$. The ferroelectric character of $SrAlF_5$ is evidenced by the reversal of the spontaneous polarization in a hysteresis loop. The higher potential of $SrAlF_5$ in comparison with $BaMgF_4$ for the realization of all-solid-state lasers in the ultraviolet wavelength region by the quasi-phase matching (QPM) technique is pointed out. $SrAlF_5$, besides a higher grade of transparency, shows a nonlinear effective coefficient similar to that of quartz and uniaxial nature, on contrast to the one order smaller nonlinear coefficient and biaxial character of $BaMgF_4$. The refractive index of $SrAlF_5$ from the ultraviolet to the near-infrared wavelength region is measured by the minimum deviation method. The Sellmeier and Cauchy coefficients are obtained from the fits to the curves of the ordinary and extraordinary refractive indices, and the grating period for the first order QPM is estimated as a function of the wavelength. The poling periodicity for 193 nm SHG from 386 nm is $4{\mu}m$.
Nan Ei Yu,Changsoo Jung,고도경,Jongmin Lee,Kenji Kitamura,Oleg A Louchev,Sunao Kurimura 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.2I
Thermal dephasing was observed in a periodically poled stoichiometric LiTaO3 crystal during second-harmonic generation at high input power. The dephasing was computationally analyzed using a thermo-optical model consisting of a coupled second harmonic process with absorption and a related temperature distribution. The computational results show a coupled spatio-temporal nanosecond pulse evolution of the fundamental and the second harmonic energy with associated temperature fields, leading to thermal dephasing and inhibition of second-harmonic generation at 1064 nm. The onset of strong non-uniform heat generation and a temperature distribution along the direction of propagation of laser beam take place, depending on the input power, due to linear and nonlinear absorption. A practical temperature adjustment is suggested to compensate the non-uniform thermal distribution and to enhance the conversion efficiency at high input powers.
Eugene G. Gamaly,Saulius Juodkazis,Vygantas Mizeikis,Hiroaki Misawa,Andrei V. Rode,Wieslaw Z. Krolikowski,Kenji Kitamura 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4
We report on a three-dimensional single-shot optical recording by 150 fs pulses at 800 nm wavelength in Fe-doped and stoichiometricundoped LiNbO 3. The highest refractive index modulation of. 10. 3 per single pulse has been achieved at close to the dielectric break-down irradiance of. TW/cm2, and was found to be independent of polarization of the writing beam. The quasi-permanent and rewrit-able bits have been demonstrated in Fe-doped LiNbO3. Recording in undoped stoichiometric LiNbO3 was of transient nature with fulloptical contrast recovery on a 0.11 s scale. The observed refractive index modulation is explainable by the photovoltaic eect inLiNbO 3.