I’ve been curious how many working researchers we’ve got in this community, and what you all do!
If you’re working in science (physical or social), engineering, etc in a research capacity, give a shout in the comments and let us know what you work on! Same goes for students and amateur scientists at any level. (And by amateur I mean those of you who are working on your own experiments but just not being paid for it / not working on a degree; I’m upset that “amateur” has a negative connotation, it shouldn’t.)
I’m currently a PhD candidate, working on transmission electron microscopy and electronic materials (mainly ferroelectrics). In the past I’ve been involved in research / product development in a few different industries, including medical devices, aerogels, and materials for RF devices.
That’s pretty fascinating stuff! I know a lot about electron diffraction in general (in the context of TEM/STEM/4D-STEM), but not ultrafast. What kind of processes were you studying with that method?
Our beamline is still very new (my main focus was actually on building/commissioning it), so for now, we’ve just been looking at relatively simple processes like the Debye-Waller effect, where the diffraction spots become weaker as the temperature rises.
The ultrafast capability comes from the electron beam having a sub-picosecond duration, which essentially corresponds to the shutter speed of a camera. By varying the delay between a pump laser and the electron probe and observing the change in intensity of the diffraction spots, we can figure out how the heat deposited by the laser diffuses through the sample, and make a “molecular movie” of this process. It’s in the same spirit as other pump-probe experiments, like what @Salamander does.
Oh wow, setting up a whole new beamline must have been quite the undertaking!
I actually do a lot of STEM simulations and having accurate Debye-Waller parameters is pretty important to get quantitatively accurate simulations of high-angle annular dark field images (since a lot of the intensity scattered out to those angles is due to thermal diffuse scattering in the crystal). So while they may be (comparatively) simple experiments, know that there are definitely those of us who really appreciate having access to the results!