Simultaneous Terahertz Pulse Generation and Manipulation with Spintronic Coding Surface

The utilization of spintronic terahertz (THz) emitters has a significant influence on broadband coherent spectroscopy and imaging at THz frequencies. By using femtosecond light to irradiate the spintronic heterostructures, spin currents from the ultrafast demagnetization effect can be transformed into charge currents through the inverse spin Hall effect, leading to the emission of THz waves. In this work, through the incorporation of sequential and inverse deposition of W-Co20Fe60B20-Pt heterostructure films, control is gained over the spin currents and THz waveforms, enabling it to achieve a 180 degrees phase difference across a broad frequency spectrum while efficiently radiating THz waves. This, in turn, allows it to control the spatial phase of THz radiation. To test the device's capabilities, lithography-based devices capable of focusing, producing vortexes, and dividing beams are manufactured. This investigation aims to advance the development of THz pulse sources while providing essential support for cutting-edge technologies such as THz spectroscopy, high-resolution imaging, and high-speed communications.