By Bradley J. Siwick (Associate Professor, Canada Research Chair in Ultrafast Science, Chemistry, McGill).
Microscopy - the science of investigating objects too small to be seen by the naked eye - has a long and rich history. Scientists have always strived to improve their view of the microscopic world in order to bring new objects and phenomena into focus. Recent years have seen rather spectacular developments in this regard. In this talk I will take you on a tour through this new microscopy technology (most of which does not look anything like what you might expect from a microscope) and describe what we can learn by using it. In modern laboratories it is now rather commonplace to be able ‘see atoms’. With these new microscopy tools we know what species they are, how they interact with their neighbours and can even pick them up and move them to new locations. We can determine the structure of individual protein molecules and are getting close to being able to watch them as they perform their function. We can make atomic-level movies of chemical reactions and image materials and cells in 3D. All of this was the stuff of Science fiction not so long ago.
Research in the Siwick laboratory is focused on developing technologies that will allow complex transient structures of molecular and material systems to be determined at the atomic level. In particular, this involves engineering new instruments that unite the tools and techniques of electron microscopy with those of time-resolved (ultrafast) laser spectroscopy in novel ways. They study photoinduced phase transitions in materials (order-disorder and order-order), where it will be possible to directly determine the changes in atomic configuration that accompany the system’s progress along the physical pathway between phases. These techniques arel also employed to try and understand structural dynamics in functional light-activated nanocomposite, nanostructured and organic materials.