Fig. 5: Pump–probe time-resolved CD absorption spectroscopy in BiH.

a Imaginary part of the dielectric function for the driven system (pumped with a circularly polarized pulse with a wavelength of 3000 nm and intensity 7.5 × 10¹¹W cm^–2), probed with either left (LCP) or right (RCP) helical probes. The driven system is temporally probed one cycle before the end of the pump laser field. The CD curve represents the subtraction between the RCP and LCP curves and is shifted down for clarity. Note that due to its finite duration, the probe pulse has a non-uniform ellipticity in this frequency region, which is not taken into account in (a). b Attosecond-resolved CD in the linear driving case (for a wavelength of 3000 nm and intensity 3 × 10¹²W cm^–2, driven at an angle of θ = 20⁰). The x-component of the driving electric field and the induced magnetization is plotted out of scale for reference in black (top), where positive/negative parts of the induced magnetization are highlighted by blue/red colors (bottom) in correspondence with the CD. The CD in (b) is normalized by the ellipticity of the probe pulse for each frequency region.