Terahertz Modulation of Even-order Polarization in GaAs

• Published in: IEEE photonics journal Vol. 17; no. 1; pp. 1 - 4
• Main Authors: Sang, Jianhua, Huang, Haoyu, Song, Liwei, Tian, Ye, Li, Ruxin
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.02.2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Crystal structure; Crystals; Electric fields; Field strength; Frequency conversion; Gallium arsenide; Harmonic analysis; Harmonic generations; Induced polarization; Modulation; Optical polarization; Optical pulses; Power harmonic filters; Silicon; Symmetry; terahertz; Terahertz frequencies; Terahertz radiation; Ultrafast measurements; ultrafast nonlinear processes; ultrafast spectroscopy; Vibration analysis
• ISSN: 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2025.3526152

The application of electric fields induces changes in the symmetry of crystals, which can be observed spectroscopically as variations in the even harmonic generation. In this study, we report the ultrafast modulation of GaAs crystal symmetry using strong terahertz field. The modulation is recorded by the vibration of even harmonic intensity which depends on the polarization direction and instantaneous field strength of applied terahertz wave. The interference between intrinsic even-order nonlinearity and terahertz induced polarization is analyzed. This work offers a novel approach to determining key parameters, such as crystal orientation and terahertz field strength.