Bayesian approach for the optimal control of high-order harmonics for the generation of ultrashort attosecond laser pulses

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Vol. 54; no. 21; pp. 21 - 26
• Main Authors: Wang, Wei-Teng, Sheu, Yae-Lin, Chu, Shih-I
• Format: Journal Article
• Language: English
• Published: IOP Publishing 03.11.2021
• Subjects: attosecond laser pulse; Bayesian optimal control; high-harmonic generation; strong field
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/1361-6455/ac3b3e

Abstract We present an efficient and powerful method to optimize the production of high-order harmonic generation (HHG) and the synthesis of an isolated attosecond pulse. The system under investigation is the helium atoms that are exposed to the combination of chirped two-color mid-IR laser field and its 1s–2p transition frequency. An ab initio study is conducted by solving the three dimensional time-dependent Schrödinger equation accurately and efficiently by means of the time-dependent generalized pseudospectral method. We applied Bayesian optimization to obtain an optimal laser waveform to generated a HHG spectrum with enhanced harmonics and extended cutoff frequency. Harmonic phases are analysed by the wavelet transform. We demonstrated that an isolated 10 attosecond pulse can be synthesized using a sequence of consecutive and phase-locked harmonics in the plateau region.