Xi 'an Institute of Optics has made progress in the research of ultrashire laser pulse light field measurement

Recently, the Attosecond Science and Technology Research Center of Xi 'an Institute of Optics and Machinery has made important progress in the research of ultrashort laser pulse light field measurement. The research team innovatively proposed a three-order nonlinear process all-optical sampling method based on perturbation, which can measure the pulse width as short as subperiod, and the band covers deep ultraviolet to far infrared. The method has the advantages of simple and stable system structure and simple data processing. The two studies were published in Optics Letters. The first authors of the paper are special Research Assistant Huang Pei and doctoral student Yuan Hao, and corresponding authors are researcher Cao Huabao and Researcher Fu Yuxi.

Ultrashort laser pulse is an important tool to explore the microcosmic world of matter and generate attosecond pulses, and its complete field waveform diagnosis is particularly important. At present, the commonly used characterization techniques can be broadly divided into frequency domain measurement and time domain measurement. In the frequency domain, there are some main methods, such as frequency resolved optical gating (FROG), spectral phase interferometry (SPIDER) and dispersion scanning (D-SCAN), which can obtain the pulse width and phase indirectly by measuring the spectral information generated by the nonlinear process. This kind of method is widely used because the device is simple and easy to set up, but usually requires a complex inversion iterative algorithm, and it is difficult to obtain the photoelectric field information, and limited by the phase matching mechanism, it is difficult to apply to the laser pulse measurement above the frequency range. The measurement method based on time-domain sampling is usually not limited by the strict phase matching, and is sensitive to the electric field waveform, and can be used to directly measure the photoelectric field, and has a good development momentum in recent years. The research team proposed an all-optical sampling method based on perturbation third-order nonlinear process, which is a time-domain sampling measurement method. In the experiment, the transient grating effect (TGP) and the Air tripling effect (AIR-THG) were respectively applied to accurately measure the output multi-period pulse (750-850nm) of the titanium gem laser. 25fs), based on the low-period pulse generated by the aerated hollow fiber post-compression technology (600-1000nm, 7.2fs) and the double-chirped optical parametric amplification system (1300-2200nm, 15fs), the ultra-short pulse measurement covering the visible, near infrared to mid-infrared bands is realized, which can meet the needs of ultra-short pulse measurement in different bands.

FIG. 1 Schematic diagram of the experimental device

FIG. 2 Measurement results of periodic pulse in visible band

FIG. 3 Measurement results of periodic pulse in mid-infrared band