Sowade Rosita, Breunig Ingo, Cámara Mayorga Iván, Kiessling Jens, Tulea Cristian, Dierolf Volkmar, Buse Karsten
Institute of Physics, University of Bonn, Wegelerstr. 8, D-53115 Bonn, Germany.
Opt Express. 2009 Dec 7;17(25):22303-10. doi: 10.1364/OE.17.022303.
Here, we present a continuous-wave optical parametric terahertz light source that does not require cooling. It coherently emits a diffraction-limited terahertz beam that is tunable from 1.3 to 1.7 THz with power levels exceeding 1 microW. Simultaneous phase matching of two nonlinear processes within one periodically-poled lithium niobate crystal, situated in an optical resonator, is employed: The signal wave of a primary parametric process is enhanced in this resonator. Therefore, its power is sufficient for starting a second process, generating a backwards traveling terahertz wave. Such a scheme of cascaded processes increases the output power of a terahertz system by more than one order of magnitude compared with non-resonant difference frequency generation due to high intracavity powers. The existence of linearly polarized terahertz radiation at 1.35 THz is confirmed by analyzing the terahertz light with metal grid polarizers and a Fabry-Pérot interferometer.
在此，我们展示了一种无需冷却的连续波光参量太赫兹光源。它能相干地发射出衍射极限的太赫兹光束，该光束在1.3至1.7太赫兹范围内可调，功率超过1微瓦。采用了位于光学谐振腔内的一块周期极化铌酸锂晶体中两个非线性过程的同时相位匹配：一个主参量过程的信号波在该谐振腔内得到增强。因此，其功率足以启动第二个过程，产生反向传播的太赫兹波。与由于腔内功率高而非共振差频产生相比，这种级联过程方案使太赫兹系统的输出功率提高了一个多数量级。通过用金属栅偏振器和法布里 - 珀罗干涉仪分析太赫兹光，证实了在1.35太赫兹处存在线偏振太赫兹辐射。
