Research

Understanding how energy and charge move through materials is central to many modern technologies, including solar cells, LEDs, and optical sensors. At the most fundamental level, these processes are governed by quantum mechanics and occur on extremely short timescales—often within femtoseconds (10⁻¹⁵ seconds) after light is absorbed. At the same time, the long-time evolution of these excitations determines how efficiently a device can transport charge and generate usable electrical energy. Our research therefore aims to bridge these two perspectives: understanding the fundamental physics of light–matter interactions on ultrafast timescales, while also investigating how these processes ultimately influence the performance of real materials and devices. 

FUNDAMENTAL QUESTIONS

A central focus of our work is understanding quantum transport of energy and charge at nanometer length scales immediately after light absorption. To probe these dynamics, we develop and apply ultrafast multidimensional spectroscopies and nonlinear optical techniques, including coherent four-wave mixing, which use carefully controlled sequences of femtosecond laser pulses to reveal correlations between electronic and vibrational motions.

These measurements allow us to explore how electron–phonon interactions, vibronic coupling, and quantum coherence influence the delocalization and transport of excitations in complex materials. We are particularly interested in combining spectroscopy with coherent nonlinear optical imaging, such as four-wave mixing microscopy, to spatially resolve excitonic and electronic dynamics. Such approaches enable defect metrology in quantum materials, allowing us to directly visualize how defects, disorder, and local structure control the fundamental processes that determine material functionality.

Our current systems of interest include electronic polaritons, light-harvesting aggregates, photosynthetic proteins, singlet-fission materials, inorganic perovskites, and layered two-dimensional materials.

APPLIED OPTICS

In parallel, we develop new optical instruments and portable hyperspectral imaging approaches that extend our work into applied dimensions such as defect metrology of semiconductors and early diagnosis. 

For instance, by combining ultrafast spectroscopy with hyperspectral imaging, we can map how excitations move, separate, or decay across real materials and devices. These tools allow us to investigate how defects, grain boundaries, morphology, and interfaces influence carrier transport and loss mechanisms in photovoltaic and optoelectronic materials. Insights from these studies help guide the design of more efficient materials and devices.

Students in the group work on projects spanning ultrafast laser experiments, nonlinear optics, optical instrumentation, theoretical modeling, and scientific data analysis pipelines, providing opportunities for students from physics, physical chemistry, applied optics, and engineering backgrounds.

Please go over our recent publications for a flavor of the experimental and theoretical work carried out in the group.