Lim Hwan-Hong, Prakash Om, Kim Byeong-Joo, Pandiyan Krishnamoorthy, Cha Myoungsik, Rhee Bum Ku
Department of Physics, Pusan National University, Busan 609-735, Korea.
Opt Express. 2007 Dec 24;15(26):18294-9. doi: 10.1364/oe.15.018294.
We report on efficient collinear optical parametric generation (OPG) with gain band ranging from 1400 to 2600 nm in a 2 cm-long periodically poled lithium niobate (PPLN) crystal. Such an ultra-broad gain band was obtained by choosing the pump wavelength at 933 nm, at which the group-velocities of the signal and the idler match near the degeneracy point. High OPG efficiency was obtained by quasi-phase matching (QPM). The ultra-broadband OPG led to efficient collinear RGB generation from a single PPLN crystal at a fixed pump wavelength. The green and red beams were found to be originating from high-order QPM sum-frequency generation between the pump and selected frequencies in the OPG band, while the blue beam was high-order QPM second-harmonic generation of the pump.
我们报道了在一块2厘米长的周期性极化铌酸锂（PPLN）晶体中实现高效共线光学参量产生（OPG），其增益带宽范围为1400至2600纳米。通过选择933纳米的泵浦波长获得了如此超宽的增益带宽，在该波长下信号光和闲频光的群速度在简并点附近匹配。通过准相位匹配（QPM）获得了高OPG效率。这种超宽带OPG使得在固定泵浦波长下从单个PPLN晶体中高效产生共线的红、绿、蓝光成为可能。发现绿光和红光源自泵浦光与OPG波段中选定频率之间的高阶QPM和频产生，而蓝光则是泵浦光的高阶QPM二次谐波产生。
