基于超快热电效应及自旋热电子学效应的THz波产生

Terahertz emission via ultrafast thermoelectric effects and ultrafast spin caloritronics effects

飞秒激光泵浦光电导天线、磁性异质结构、电光晶体、空气等会产生太赫兹脉冲,其产生原理主要基于飞秒激发下载流子、电极化的瞬态变化等非热效应。与此同时,飞秒激光泵浦物质不可避免地会产生超快热效应。近年来,基于超快热电效应以及与自旋相关的超快自旋热电子学效应产生太赫兹波获得越来越多的关注。本文详细介绍了利用塞贝克效应/能斯特效应这两种热电效应,以及自旋塞贝克效应/反常能斯特效应这两种自旋热电子学效应产生太赫兹波的研究进展。超快热电效应及超快自旋热电子学效应已在太赫兹产生方面展现出巨大潜力,有望推动太赫兹源及相关技术的发展。

Terahertz(THz) pulses can be generated by pumping photoconductive antennas,magnetic heterostructures,electro-optic crystals,and air,etc.with femtosecond lasers,which are mainly based on non-thermal effects such as transient changes in carriers and electric polarization under femtosecond excitation.Meanwhile,the laser heating effects inevitably occur during the interactions of femtosecond lasers with matter,and the ultrafast thermoelectric effects and the ultrafast spin caloritronics effects have gained increasing attention in recent years for the ability to generate terahertz waves.In this paper,the research progresses of THz emission induced by two ultrafast thermoelectric effects including the Seebeck effect and the Nernst effect,and two ultrafast spin caloritronics effects including the spin Seebeck effect and the anomalous Nernst effect,are introduced in detail.The ultrafast thermoelectric effects and the ultrafast spin caloritronics effects have exhibited great potential in terahertz generation,which could promote the development and the applications of THz sources and related technologies.