Open AccessTerahertz emission from ultrafast ionizing air in symmetry-broken laser fields
Author(s) -
Ki-Yong Kim,
J. H. Glownia,
Antoinette J. Taylor,
George Rodriguez
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.004577
Subject(s) - terahertz radiation , laser , optics , photomixing , terahertz spectroscopy and technology , electric field , ultrashort pulse , terahertz gap , photocurrent , physics , electromagnetic pulse , far infrared laser , optoelectronics , materials science , terahertz metamaterials , quantum mechanics
A transient photocurrent model is developed to explain coherent terahertz emission from air irradiated by a symmetry-broken laser field composed of the fundamental and its second harmonic laser pulses. When the total laser field is asymmetric across individual optical cycles, a nonvanishing electron current surge can arise during optical field ionization of air, emitting a terahertz electromagnetic pulse. Terahertz power scalability is also investigated, and with optical pump energy of tens of millijoules per pulse, peak terahertz field strengths in excess of 150 kV/cm are routinely produced.