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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.
Parasitic-light-suppressed quasi-phase-matched optical parametric oscillation device.
Lim, Hwan Hong,Kurimura, Sunao,Yu, Nan Ei Optical Society of America 2014 Optics express Vol.22 No.5
<P>Nonlinear absorption - such as green-induced infrared absorption (GRIIRA) - increases the risk of the catastrophic damage during high peak- power wavelength conversion. We propose a novel concept to suppress parasitic green second-harmonic generation (SHG) in optical parametric oscillation (OPO) using specially engineered quasi-phase-matched (QPM) structures. This selective suppression was achieved by relative π-phase shift in only SHG not OPO. Compared with a periodic device, a parasitic-light-suppressed (PLS) QPM device produced smaller normalized conversion efficiency in green and maintained singly resonant OPO performance.</P>
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.
이종훈,Hideo Ishizuki,Ichiro Shiji,Sunao Kurimura,Takunori Taira 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.2
Signal and idler wave spectra from an optical parametric oscillator were analyzed. Quasi phase matching in 5 mol.% MgO-doped periodically poled lithium niobate was used to generate infrared radiation. The dependences of the wavelengths of the signal and idler waves on the grating period and the temperature were precisely measured. The wavelengths of the signal and the idler waves deviated considerably from the predictions of Sellmeier equation, especially near the degenerate point.
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.