Paper
12 October 2020 THz research on high-frequency waves under different ionization modes
Ji Zhao, Xiaojian Li, Guang Yang, XiuLi Nie, Xiaolin Du, Tiannan Wang
Author Affiliations +
Abstract
The high-frequency waves-Terahertz (THz) emission from laser-induced air-plasma is presented. The development of high power and high efficiency THz wave radiation source has significant value. The development of laser technology has led spectroscopic sensing and imaging in the THz region to be widely employed in diverse fields such as material characterization, ultrafast dynamic process studies, and biological science. The emission of THz waves has become one of the most important areas in THz research. In this research, we develop an THz time-domain spectroscopy system(THz- TDS), which is that the input laser pulses are generated from a p-polarized regenerative Ti:sapphire amplifier with a 50- fs pulse duration centered at 800 nm. A 100-μm-thick type-I BBO crystal is employed for frequency doubling the pump pulses and subsequently generating the THz wave. By this setup we investigate that when the terahertz emission from only fundamental wave and with second-harmonic wave mixing, the intensity of the terahertz wave obtained is different. The energy of THz wave generated by only fundamental wave is weak, and that generated by four wave mixing is stronger. The energy intensity of THz wave generated by four wave mixing is much higher than that of THz wave generated by fundamental wave (almost an order of magnitude higher). We believe that the different ionization modes causes the different of terahertz wave energy intensity. In addition, we find that the second harmonic wave grows in a quadratic curve with the increase of pump energy, so we believe that when the pump energy increases, the terahertz wave also grows in a quadratic curve.
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ji Zhao, Xiaojian Li, Guang Yang, XiuLi Nie, Xiaolin Du, and Tiannan Wang "THz research on high-frequency waves under different ionization modes", Proc. SPIE 11559, Infrared, Millimeter-Wave, and Terahertz Technologies VII, 115590N (12 October 2020); https://doi.org/10.1117/12.2573340
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KEYWORDS
Terahertz radiation

Ionization

Four wave mixing

Spectroscopy

Biosensing

Imaging spectroscopy

Laser applications

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