Open AccessEnhancement of terahertz waves from two-color laser-field induced air plasma excited using a third-color femtosecond laser
Author(s) -
Danni Ma,
Liquan Dong,
Minghao Zhang,
Tong Wu,
Yuejin Zhao,
Liangliang Zhang,
Cunlin Zhang
Publication year - 2020
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.395130
Subject(s) - terahertz radiation , laser , optics , femtosecond , materials science , far infrared laser , optoelectronics , physics
This study experimentally demonstrates and theoretically analyzes the enhancement of terahertz (THz) waves from two-color laser-field (consisting of a near-infrared femtosecond laser and its second-harmonic wave) induced air plasma using an additional 800 nm femtosecond laser. The experiments revealed that the additional 800 nm laser increased the THz energy up to 22 times. To understand the enhancement mechanism and reveal the maximum enhancement conditions, the effects of the 800 nm beam's polarization and energy variations of both beams on the THz amplification were studied. With the increase in the 800 nm pulse energy, the THz yield initially increases, and then decreases after reaching an inflection point. The THz increase rate continues to increase with the decrease in energy of the near-infrared two-color fields. The 800 nm beam could efficiently modulate the THz spectral energy distribution by increasing the high-frequency components, while decreasing the low-frequency components.