Signatures of coherent propagation of blue polaritons in Cu 2 O
Signatures of coherent propagation of blue polaritons in Cu 2 O
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Cu 2 O中蓝色极化子的相干传播特征
DOI：
10.1103/physrevb.87.245202
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发表时间：
2013
影响因子：
3.7
通讯作者：
Manfred Bayer
中科院分区：
文献类型：
--
作者：
Johannes Schmutzler;Dietmar Fröhlich;Manfred Bayer
双共振和频产生（SFG）在CuO中被证明。黄色的正激子-极化激元被单频染料激光共振激发（四极跃迁），并被单频红外激光耦合到蓝色的正激子-极化激元（偶极跃迁）。测量了两束泵浦激光平行和反平行时的和频（SF）谱随红外激光能量的变化。在反平行配置，观察到明显的振荡与晶体长度成反比的周期缩放。这些振荡的起源进行了详细讨论，并归因于相位匹配效应。如果由SFG产生的蓝色极化激元在晶体中相干移动，就可以理解相位匹配的出现。这一观察结果是非常令人惊讶的，因为在单光子传输实验中激发的蓝色激子-极化激元仅由于强散射而表现出吸收长度。
Double resonant sum-frequency generation (SFG) is demonstrated in CuO. Theyellow orthoexciton-polariton is resonantly excited by a single frequency dye laser (quadrupole transition) and coupled to the blueexciton-polariton by a single frequency infrared laser (dipole transition). Sum-frequency (SF) spectra as a function of the energy of the infrared laser are measured for the two pump laser beams parallel and antiparallel. In the antiparallel configuration, pronounced oscillations are observed with a period scaling inversely with the crystal length. The origin of these oscillations is discussed in detail and attributed to a phase-matching effect. The appearance of phase matching can be understood if the blue polaritons—generated by SFG—move coherently through the crystal. This observation is very surprising, since blue exciton-polaritons excited in a one-photon transmission experiment exhibit an absorption length of onlydue to strong scattering.