Universality in odd-even harmonic generation and application in terahertz waveform sampling

Chúng tôi vui mừng thông báo rằng TS. Lê Thị Cẩm Tú và các đồng nghiệp gần đây đã xuất bản công trình của họ có tựa đề "Universality in odd-even harmonic generation and application in terahertz waveform sampling" trên tạp chí Physical Review A.

Tóm tắt:

Odd-even harmonic generation contains the system's dynamical symmetry breaking, and its decoding is desirable not only in understanding physics but also for applications of dynamics extraction. In this work we discover a simple universal relation between the odd-even harmonics and the asymmetry of the terahertz (THz)-assisted laser-atomic system: atoms in a primary midinfrared laser pulse combined with a THz laser. We demonstrate numerically and then derive analytically the dependence of the harmonic even-to-odd ratio on the THz electric field. Notably, the functional form of this dependency reveals a universal scaling independent of the parameters of both the primary pulse and atomic target. This universality inspires us to propose a pump-probe scheme for THz waveform sampling from the even-to-odd ratio, accessible from conventional compact setups.