Emerging ultrafast techniques for studying quantum materials

Photocatalysis with atomically thin sheets

“…Femtosecond transient absorption spectroscopy (fs-TAS) is a well-known time-resolved spectroscopy technique. 86 It is a combination of the ultrafast pump-probe technology and the absorption spectroscopy. 87 Typically, it uses a well-defined pump pulse (high-energy femtosecond monochromatic pulse) to excite the sample to the excited state, and then monitors the relaxation process back to the ground state via a time-delayed probe pulse (low-energy white pulse) (Fig.…”

“…For detailed information about these time-resolved spectroscopy techniques, the reader is referred to a number of recent articles. 86,[93][94][95] 3.3.3. Space-resolved techniques.…”

Disentangle electronic, structural, and spin dynamics using transient extreme ultraviolet spectroscopy

“…Recent advances in laser and accelerator technologies have enabled ultrafast X-ray sources and their applications in materials science. [42][43][44][45][46][47][48][49][50][51][52][53] Ultrafast X-ray spectroscopy combines sensitivity to element-specific local chemical information with unprecedented temporal resolution. [54][55][56][57][58][59][60][61][62][63] For example, ultrashort coherent X-ray pulses with durations from tens of femtoseconds to attoseconds have been generated at tabletop setups and accelerator facilities.…”

“…Photoexcitation could potentially launch coupled charge, lattice, and spin dynamics. 1,6,53 These dynamics are probed with dipole-allowed core-to-valence XUV transitions. Fig.…”

Ultrafast Condensed Matter Physics at Attoseconds

“…More details on these spectroscopies are well reviewed in recent literature. [23][24][25] Moreover, by combining with attosecond laser pulse as well as the pump-probe setup, researchers also equipped conventional imaging techniques with the attosecond resolution, realizing the attosecond scanning tunnelling microscopy (ASTM) and the attosecond transmission electron microscopy (ATEM).…”