de Jong J A, Kalashnikova A M, Pisarev R V, Balbashov A M, Kimel A V, Kirilyuk A, Rasing Th
Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen, Netherlands.
J Phys Condens Matter. 2017 Apr 26;29(16):164004. doi: 10.1088/1361-648X/aa5e94. Epub 2017 Mar 21.
Light propagation effects can strongly influence the excitation and the detection of laser-induced magnetization dynamics. We investigated experimentally and analytically the effects of crystallographic linear birefringence on the excitation and detection of ultrafast magnetization dynamics in the rare-earth orthoferrites (SmPr)FeO and (SmTb)FeO, which possess weak and strong linear birefringence, respectively. Our finding is that the effect of linear birefringence on the result of a magneto-optical pump-probe experiment strongly depends on the mechanism of excitation. When magnetization dynamics, probed by means of the Faraday effect, is excited via a rapid, heat-induced phase transition, the measured rotation of the probe pulse polarization is strongly suppressed due to the birefringence. This contrasts with the situation for magnetization dynamics induced by the ultrafast inverse Faraday effect, where the corresponding probe polarization rotation values were larger in the orthoferrite with strong linear birefringence. We show that this striking difference results from an interplay between the polarization transformations experienced by pump and probe pulses in the birefringent medium.
光传播效应会强烈影响激光诱导磁化动力学的激发与探测。我们通过实验和分析研究了晶体线性双折射对稀土正铁氧体（SmPr）FeO和（SmTb）FeO中超快磁化动力学激发与探测的影响，这两种材料分别具有弱线性双折射和强线性双折射。我们的发现是，线性双折射对磁光泵浦 - 探测实验结果的影响很大程度上取决于激发机制。当通过法拉第效应探测的磁化动力学是由快速的热诱导相变激发时，由于双折射，探测脉冲偏振的测量旋转会受到强烈抑制。这与超快逆法拉第效应诱导的磁化动力学情况形成对比，在具有强线性双折射的正铁氧体中，相应的探测偏振旋转值更大。我们表明，这种显著差异源于双折射介质中泵浦脉冲和探测脉冲所经历的偏振变换之间的相互作用。
