From outstanding undergraduate researcher to CQT PhD student

Earning the Outstanding Undergraduate Researcher Prize, Yeo Xi Jie (pictured right) worked in the lab of Christian Kurtsiefer at CQT for two years before starting his PhD this summer.

Yeo Xi Jie got a taste for quantum technologies before he even left school. The PhD student, who enrolled in CQT’s PhD programme in August this year, first worked in a CQT lab when he was still a junior college student.

Xi Jie’s long commitment paid off this year with his recognition by the National University of Singapore (NUS) as an outstanding undergraduate researcher. He won one of only six prizes awarded to science students for the 2018-19 academic year. The details were announced in the NUS Faculty of Science Annual Report published in December.

When he was a second-year physics student in 2017, Xi Jie started working on quantum optics in the group of CQT Principal Investigator Christian Kurtsiefer. “Through the mentorship of everyone, I was able to further my technical skills in the lab as well as knowledge in the realm of quantum physics,” he says. He continued with the group to complete his final year project on “Spectral Compression of Narrowband Single Photons”.

His research concerned the frequency of light emerging from a single-photon source. Using time-lenses to manipulate the photons in the time-frequency domain, the group showed they could compress the frequency distribution of infrared photons by a factor of two. 

These compressed photons give a closer match for the spectrum of atomic transitions, useful in quantum information protocols that require the transfer of information between light and matter. For example, photons may fly information around a network, while atoms store and process data. Such schemes are building blocks for a future quantum internet.

The results are being written up for publication, and the work has already been presented at conferences including the international Conference on Lasers and Electro-Optics (CLEO) held in San Jose, California, in May 2018, and the DPG Fall Meeting in Freiburg, Gemany in September 2019.

His first experience in CQT when he was a college student was in the lab of Principal Investigator Rainer Dumke at the Nanyang Technological University. “That was when I found that I really enjoyed doing hands-on work,” he says. Since establishing himself in Christian’s group during his undergraduate degree, he stays under Christian’s supervision for his PhD.

In a testimonial written for the Faculty of Science, Xi Jie says “I would like to thank Centre for Quantum Technologies for providing such a lovely environment here which facilitates productive collaboration and discussion between scientists and aspiring scientists interested in the field of quantum technologies.” In turn, we thank Xi Jie for deciding to stay at CQT to continue his research towards a PhD!