Seminar

Experimental strong-field physics is a fast-growing area of nonlinear optics, triggered by the development of isolated attosecond (as) pulses (IAP) / attosecond pulse trains (APT). The extreme-ultraviolet (EUV or XUV) pulses exhibit exceptional laser-like properties, providing attosecond time-scales and angstrom space-scale resolution. Hence, these pulses are promising candidates to investigate a broad class of atomic and/or molecular ultra-fast processes in real-time via techniques based on attosecond spectroscopy enabling the observation of inner electron dynamics in the field of AMO sciences. Studies on charge migration and intermediate auger processes during ionization, femtosecond (fs) pump-probe spectroscopy with attosecond precision, high-resolution imaging, and nonlinear optics in the XUV photon energies, attosecond chemistry, are some of the experiments feasible via as pulses. Attosecond pulses are generated through the process of high-order harmonic generation (HHG), described by the well-known three-step model, which commences by tunnel ionization of an atom/molecule occurring in the presence of an intense ultrashort laser pulse. The wave function of the outer electron splits into two parts; a free and bound part, where the free part follows the changes in the laser field and returns to the parent ion after approximately one half-cycle of the driving laser and interferes with the bound part, releasing the energy acquired during this process as a high-energy photon. A spectrum consisting of the frequency comb is obtained, along with a continuum, due to the interference of many such processes happening in a short space and in a short time span, depending on the nature of the HHG driving pulse.

The generation of harmonics using shaped ultrashort pulses, the characterization of attosecond pulses, and various experiments realized using attosecond pulses will be discussed in this talk. In addition, the proposal to develop such a state-of-the-art laboratory, and the experiments possible within its capacity will be discussed.