Currently I am measuring the gravitational constant. The gravitational constant is a fascinating problem, over 200 years of precision measurements have failed to give a consistent result. The results are slowly converging to an answer, but still many measurements disagree with each other by far more than their uncertainty estimates should allow (See this excellent nature article.). We are currently performing a first of its kind measurement for the gravitational constant, instead of inventing a new experiment and adding another point to the scatter, we are taking a previous measurement and repeating it with a new team in a new location to hope to unveil the source of the disagreement. More detail here.
During my PhD and my first Post-Doc I concentrated on nano-scale force measurements and on scanning probe microscopy, specifically nc-AFM (non-contact atomic force microscopy) and STM (scanning tunnelling microscopy). I originally started in research by writing software to automate the in situ tip preparation for STM, before moving into combined nc-AFM/STM. My AFM work has concentrated on the mechanism for image formation and force extraction using qPlus sensors. I am now applying this to developing new sensor designs.