Enhancement Effects of a Neodymium Magnet Mount on Terahertz Electromagnetic Waves from an Ultrafast Photocurrent and Coherent LO Phonons in a GaAs-based epilayer

We succeeded in enhancing terahertz electromagnetic wave emitted from GaAs-based epitaxial layers by simply mounting a wafer chip on a neodymium permanent magnet. The terahertz waves, which originate from the ultrafast photocurrent and the coherent longitudinal optical phonon, were simultaneously enhanced. The present finding provides a simple method for enhancing terahertz wave emitted from the compound semiconductor surface illuminated by the femtosecond laser pulse.