  The Orbital Hall effect, which originates from materials with weak spin-orbit
coupling, has attracted considerable interest for spin-orbitronic applications.
Here, we demonstrate the inverse effect of the orbital Hall effect and observe
orbitronic terahertz emission in the Ti and Mn materials. Through spin-orbit
transition in the ferromagnetic layer, the generated orbital current can be
converted to charge current in the Ti and Mn layers via the inverse orbital
Hall effect. Furthermore, the inserted W layer provides an additional
conversion of the orbital-charge current in the Ti and Mn layers, significantly
enhancing the orbitronic terahertz emission. Moreover, the orbitronic terahertz
emission can be manipulated by cooperating with the inverse orbital Hall effect
and the inverse spin Hall effect in the different sample configurations. Our
results not only discover the physical mechanism of condensed matter physics
but also pave the way for designing promising spin-orbitronic devices and
terahertz emitters.
