Ling Hao

Scientist, Quantum Detection

As a child were you interested in science? Was it encouraged?

Yes, science, but not physics. My family includes lots of medical doctors like my mum. So I wanted to be a famous doctor or surgeon in China. In high school, I had a very good physics teacher, and I started coming top in the subject. My teacher gave me lots of extra physics reading… it became my favourite topic, the one I really loved, but for family reasons I still wanted to be a doctor.

At that time, less than one percent of people could go to university. I worked very hard, so when I got my exam results, they were so high I could choose any university I wanted. But the very best medical school only offered places to the top student in each of the 24 provinces. I came second, so I couldn't go. I spoke to my parents and said that in my heart I wanted to do science, so they agreed. I was awarded the top place in physics at Beijing Normal University.

How did you end up at NPL?

During my BSc I took another set of exams to get onto the MSc - only three people got it in my year. My supervisor had worked in Europe and America and that opened a door for me to the west. I also started to study theoretical physics in the MSc, and I found it very interesting. I got two papers published in the Journal of Physics, and was offered a position in America to do my PhD.

But China was not like it is now - I was not allowed to leave. I had to stay working in the country as a lecturer. Later my husband was offered a job at the University of York, and I was allowed to follow him. I did my PhD at the University of Strathclyde, and joined NPL after that, almost 20 years ago.

Tell us about your work

At NPL, scientists don't have to focus on just one small area. I mainly work on superconductivity - especially nanoSQUIDs (nanoscale superconducting quantum interference devices) for single particle detection, but I'm also looking at microwaves, as well as carbon nanotubes and graphene. I love to explore new areas.

Graphene is very interesting to industry, but it's difficult to measure because it's only one atom thick. We've done lots of modelling on it, and we're now using microwaves to measure the sheet resistance of graphene. We can do it very quickly, and because we don't touch it, we don't damage it. This will be a very important measurement for developing flexible devices.

Another thing we're looking at is proton therapy for cancer. It causes very little damage to surrounding tissues, so it's really good for patients. But there aren't many sensors that can measure how much energy is delivered to the cell each time. My superconducting device can do this, and we have funding now to develop it. This work lets me indirectly work on improving the treatment of patients, so I'm very happy.