Extended Data Fig. 8: Terahertz pulse weak-field voltage calibration.
a,b, Voltage calibration performed for the weak-field waveform on Au(111), VWF(t), following a similar procedure to Extended Data Fig. 2f. A pair of QTHz–ESF,pk curves (a) acquired at τCC = 0 ps (solid red line) and τCC = –6 ps (solid black line) are used to calibrate the weak-field voltage by translating the red curve along the x-axis by 6.3 V/cm (b), equivalent to 0.30 V. The measurements were performed on Au(111) at constant height with Vd.c. = 0 V and a 100 pm tip approach from the initial tip–sample separation set by V0 = 2 mV, I0 = 300 pA.
