The interaction between electromagnetic fields and condensed matter not only underpins much of modern technology, but also provides one of the most fundamental ways to study quantum materials. To this end, the ever expanding family of emerging phenomena in these materials calls for new electromagnetic probes working in unexplored parameter spaces. In this talk I will present two of such cases: the first metallic magnetic domain walls in a magnetic insulator discovered by near-field microwave microscopy, and terahertz (THz) electromagnetic emission by ultrafast charge transfer between two atomically thin semiconductors recorded by time-domain THz emission spectroscopy. I will also discuss the exciting opportunities provide by combining several of these techniques to create the first extreme-broadband micro-spectroscopy system.
