Validity of extracting photoionization time delay from the first moment of streaking spectrogram<xref rid="cpb_28_1_013201fn1" ref-type="fn">*</xref><fn id="cpb_28_1_013201fn1"><label>*</label><p>Project supported by the Talent Introduction Foundation of Qiannan Normal University of Nationalities, China (Grant No. qnsyrc201619), Natural Science Foundation of Guizhou Provincial Education Department for Young Talents, China (Grant No. Qian Education Contract KY[2017]339), and Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Grant No. DE-FG02-86ER13491).</p></fn>

Validity of extracting photoionization time delay from the first moment of streaking spectrogram**

Project supported by the Talent Introduction Foundation of Qiannan Normal University of Nationalities, China (Grant No. qnsyrc201619), Natural Science Foundation of Guizhou Provincial Education Department for Young Talents, China (Grant No. Qian Education Contract KY[2017]339), and Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Grant No. DE-FG02-86ER13491).

Wei Chang-Li¹, Zhao Xi^{2, †}

(a) The COE E¯(td) calculated from the two spectrograms for target A shown in Fig. 3, using both the 197 as TL XUV and the 410 as chirped XUV. (b) A zoom-in plot near t_d = 0 from which one can extract the time delay τ^s in Eq. (18).