Speaker: Keith Nelson, MIT
Program Description
The present audience probably doesn’t need convincing that coherent ultrashort x-ray pulses offer tantalizing prospects for condensed matter spectroscopy. Coming from the optical spectroscopy perspective, there are myriad ways in which x-rays can provide key new insights. I’ll illustrate several with examples of work done recently or under way currently, and in each case I’ll suggest what further advances in x-ray optics or spectroscopy capabilities could yield important further advances in what we could learn through nonlinear spectroscopy. The three motivating classes of experiment that I’ll discuss are optical or THz pump, x-ray probe; x-ray transient grating pump, x-ray probe; and more general x-ray four-wave mixing and two-dimensional spectroscopies. These experiments exploit progressively more characteristics of the x-ray fields: short pulse duration; spatial coherence; and full temporal and spatial coherence.
