Achievement

Creating an intense and broadband circular polarized terahertz (THz) wave has always been an obstacle in the THz community, which limits the possible applications of THz waves in biology and spintronics. IGERT trainee Xiaofei Lu developed a new approach to directly generate elliptically polarized THz waves from laser-induced plasma with a pair of double helix electrodes. The method was initiated from a perception of the propagation effects in the THz generation process with laser-induced plasma. It then utilized velocity mismatch between the optical beam and THz beam to manipulate the elliptical polarized THz waves, and provided an advanced concept to control plasma-based THz sources. This finding will become an essential guidance for polarization manipulation of THz waves and open a new interdisciplinary research area within the THz community.