Advent calendar - December 3rd - Xinpeng Xu

In the Zernike Institute Advent Calendar, we are presenting 24 short spotlights in December. In these specials, we highlight PhD students, postdocs, support staff and technicians of our research groups and team - providing a glimpse in their typical day at work. In Episode 3 meet Xinpeng Xu, PhD student in the Optical Spectroscopy of Functional Nanosystems (OSFN) group.

I am a fourth-year experimental PhD student in the Optical Spectroscopy of Functional Nanosystems (OSFN) group. My research focuses on “ultrafast coherent control”, a cutting-edge approach to guiding functional nanosystems towards desired applications, such as enhancing electron transport efficiency. Rather than altering the properties or morphology of the target molecules, we use shaped femtosecond (fs) laser pulses (1 fs = 10−15 s) to control the excitation dynamics of these molecules on ultrafast timescales—typically within tens to hundreds of femtoseconds. This interdisciplinary research combines physics, materials science, and physical chemistry, with physics at its core.

In our lab, we have developed and integrated an ultrafast coherent control optical stage, enabling the generation of custom-shaped laser pulses, with a microscopic-spectral detection system offering nanometer-level resolution. This system allows us to detect photoluminescence (PL) signals from the target molecules as they interact with the shaped laser pulses. By analyzing the changes in PL signal properties, such as intensity and spectral shifts, we gain insights into how the molecules respond dynamically to these precisely tailored excitations. Metaphorically, I act as a surgeon—not on patients, but on laser pulses—to “treat” molecules and optimize their functionality.

Experimental research is always full of challenges. A tiny particle on the surface of a microscope can drastically impact the results, leaving me questioning, “Where did I go wrong?” for an entire week. Looking back, the number of smiles after a long day in the lab often pales in comparison to the frustrations. So, what keeps me moving forward? It must be the desire to succeed, the unwavering encouragement and support from my supervisor, the incredible daily assistance from our “superman” technician, the warmth and camaraderie of my colleagues, and most importantly, the unconditional love and support from my wife and our adorable two-year-old daughter. I choose to embrace every moment of this journey, knowing that one day these experiences will become cherished memories.

Merry Christmas!!!