Relativistic single-cycle tunable infrared pulses generated from a tailored plasma density structure

• Published in: Nature photonics Vol. 12; no. 8; pp. 489 - 494
• Main Authors: Nie, Zan, Pai, Chih-Hao, Hua, Jianfei, Zhang, Chaojie, Wu, Yipeng, Wan, Yang, Li, Fei, Zhang, Jie, Cheng, Zhi, Su, Qianqian, Liu, Shuang, Ma, Yue, Ning, Xiaonan, He, Yunxiao, Lu, Wei, Chu, Hsu-Hsin, Wang, Jyhpyng, Mori, Warren B., Joshi, Chan
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.08.2018
• Subjects: Carrier density; Coherent radiation; Harmonic generations; Infrared radiation; Nonlinear optics; Optics; Plasma; Plasma density; Plasmas; Radiation; Radiation sources; Relativism; Relativistic effects; Wavelength
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-018-0190-8

The availability of intense, ultrashort coherent radiation sources in the infrared region of the spectrum is enabling the generation of attosecond X-ray pulses via high-harmonic generation, pump–probe experiments in the ‘molecular fingerprint’ region and opening up the area of relativistic infrared nonlinear optics of plasmas. These applications would benefit from multi-millijoule single-cycle pulses in the mid- to long-wavelength infrared region. Here, we present a new scheme capable of producing tunable relativistically intense, single-cycle infrared pulses from 5 to 14 μm with a 1.7% conversion efficiency based on a photon frequency downshifting scheme that uses a tailored plasma density structure. The carrier-envelope phase of the long-wavelength infrared pulse is locked to that of the drive laser to within a few per cent. Such a versatile tunable infrared source may meet the demands of many cutting-edge applications in strong-field physics and greatly promote their development.