Observation of a refractive index line shape in ultrafast XUV transient absorption spectroscopy

Ultrafast excessive ultraviolet (XUV) spectroscopy is a robust method for probing the dynamics of atoms and molecules with attosecond time decision. Nonetheless, typical XUV absorption measurements solely present details about the imaginary a part of the advanced refractive index, which is expounded to the absorption coefficient. The true a part of the refractive index, which describes the chromatic dispersion of the fabric, is normally inaccessible.

In a brand new examine revealed in Ultrafast Science, Mingze Solar et al. have demonstrated a novel methodology to measure the refractive index line form in ultrafast XUV transient absorption spectroscopy. They used a scheme the place the XUV pulse traverses the goal gasoline jet off-center, which induces deflection on the XUV radiation because of the density gradient of the jet. By measuring the frequency-dependent XUV deflection spectra, they have been capable of reproduce the refractive index line profile.

The researchers additionally confirmed that they might management the refractive index line form by introducing a later-arrived near-infrared pulse to change the part of the XUV free induction decay, leading to totally different XUV deflection spectra. This method allowed them to control the matter response to the XUV gentle subject and discover new bodily phenomena.

The examine reveals new insights into matter-induced absorption and deflection in ultrafast XUV spectroscopy. The true refractive index and the absorption index could also be measured concurrently, which supplies a full image of a fabric’s linear response to incident gentle.