Ultrafast electric current and terahertz radiation generation in plasmas

by Prof. Kiyong Kim (University of Maryland, USA)

Monday Jun 13, 2011, 4:00 PM → 5:00 PM Asia/Seoul

216-1호 (제1과학관)

Sandwiched between the optical and microwave regimes, far infrared or terahertz (THz) frequency has recently drawn special attention due to its potential for molecular sensing, biomedical imaging and spectroscopy, security scanners, and plasma diagnostics. For these applications, there is a growing need for high-energy, compact THz sources at a tabletop-scale. In this talk, I will present our demonstration of high-power, broadband THz radiation generation using tabletop femtosecond lasers. In this scheme, an ultrafast pulsed laser’s fundamental and second harmonic fields are mixed in a gas of atoms or molecules, causing them to ionize. The resulting plasma can generate a directional electron current and simultaneous far-field THz radiation, all coherently controlled by the laser field amplitudes and relative phase. I will also talk about phase-matching and molecular alignment effects on such THz generation, as well as THz polarization control by two-dimensional electric currents.