Terahertz (THz) time-domain spectroscopy and optical pump-THz probe spectroscopy are today widely used within the THz community to study material properties and carrier dynamics in semiconductors and 2D materials. Along with these methods, Laser THz Emission Microscopy (LTEM) is an alternative and somewhat simpler technique where THz pulses are collected from a sample after it is directly photo-excited by a femtosecond (fs) laser. Since most semiconductors intrinsically are able to emit THz pulses when carriers are accelerated on a fs time scale, this method is directly able to provide information about carrier mobility. At the same time, LTEM can image a sample with a much higher spatial resolution than conventional THz systems due to the much lower diffraction-limit of the fs laser pulses.
Recently, it has been demonstrated that spintronic THz emitters have the potential of out-competing conventional THz sources showing an impressive efficiency and a bandwidth up to 10s of THz, which is normally only achieved in much more sophisticated THz sources such as air-plasmas generated with amplified fs laser systems. While some work has already been done in optimizing the spintronic structures to generate maximum THz signal and bandwidth, understanding the carrier dynamics from the measured THz pulses is still a challenge. In this presentation we discuss the ability to understand the carrier dynamics spintronic samples with LTEM and THz time-domain spectroscopy, and present an experimental platform where samples can be studied with these methods simultaneously.
|