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Updated: Jun 22, 2026

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Terahertz emission from ultrafast ionizing air in symmetry-broken laser fields
Ki-Yong Kim1, James H Glownia, Antoinette J Taylor
1Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Los Alamos, NM 87545, USA. kykim@lanl.gov
Abstract:
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.
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