Mixing the fundamental (ω) and the second harmonic (2ω) waves in the gas phase is a widely used technique for generating terahertz pulses. The authors experimentally present an enhanced terahertz emission through the temporal-spatial manipulation of bi-focal bi-chromatic fields, and the THz radiation mainly originates from the plasma created by the 2ω pulses instead of the ω pulses, which cannot be explained only using photocurrent model.
- Jingjing Zhao
- Yizhu Zhang
- Yuhai Jiang
