Abstract
Optical noise, the core of the pulse-contrast challenge for ultra-high peak power femtosecond lasers, exhibits spatiotemporal (ST) coupling induced by angular dispersion. Full characterization of such ST noise requires two-dimensional measurements in the ST domain. Thus far, all noise measurements have been made only in the temporal domain. Here we report the experimental characterization of the ST noise, which is made feasible by extending cross-correlation from the temporal domain to the ST domain. We experimentally demonstrate that the ST noise originates from the optical surface imperfections in the pulse stretcher/compressor and exhibits a linear ST coupling in the far-field plane. The contrast on the far-field axis, underestimated in the conventional measurements, is further improved by avoiding the far-field optics in the stretcher. These results enhance our understanding of the pulse contrast with respect to its ST-coupling nature and pave the way toward the design of high-contrast ultra-high peak power lasers.
Highlights
Optical noise, the core of the pulse-contrast challenge for ultra-high peak power femtosecond lasers, exhibits spatiotemporal (ST) coupling induced by angular dispersion
The proposed ST crosscorrelator (STCC) consists of three key elementary components: an ST cross-correlation component based on sum-frequency generation (SFG), a 1D detection system that can be translated in the direction of ST coupling and a sampling laser
We demonstrated a highly sensitive detection system based on a combination of a fibre array and photomultiplier tube (PMT)[29], as illustrated in Fig. 1h, which can support a dynamic range of 41010 and 100 sampling points
Summary
The core of the pulse-contrast challenge for ultra-high peak power femtosecond lasers, exhibits spatiotemporal (ST) coupling induced by angular dispersion Full characterization of such ST noise requires two-dimensional measurements in the ST domain. Cross-correlation techniques, in either timescanning or single-shot mode, have been developed for high dynamic range measurements of pulse contrast[20,21,22,23,24,25,26,27,28,29] These measurements, which are commonly performed in the near field and are only temporally resolved, have been successful in characterizing noise without ST coupling, such as that produced in laser amplifiers[30,31,32]. Techniques capable of both temporal and spatial resolution for the characterization of ST noise are desired[12,33], especially for assessments in high-field physics in which the experimental target is located in the far field
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
