Thermal transport measurement and imaging
We demonstrated a time-resolved optical technique called vibrational-pump visible-probe (VPVP) spectroscopy, which employs direct vibrational excitation of materials by fs mid-infrared (MIR) optical pump, after which the time dependent optical transmittance across the visible range is probed in the ns to the µs time window using a broadband pulsed laser. This transducer-free VPVP method is expected to permit the investigation of dynamic lattice temperature variations in organic, polymeric, and hybrid organic-inorganic semiconductors.
Optical properties of nanostructured materials
We harvest both solution-based synthesis and vapor-phase growth techniques to fabricate thin-film and nanostructured materials. These materials and structures are exploited for energy conversion, optoelectronics, sensing, and information science applications. We are particularly interested in layered hybrid organic-inorganic perovskites and other classes of low-dimensional materials.
Excited-state dynamics of functional materials
We investigate the dynamic processes of fundamental excitations (e.g., electrons, lattice vibrations) in solid-state and solution-phase materials using time-resolved optical spectroscopy. Our spectroscopic setup covers a wide spectral range (250 nm ~ 15 µm) with ~100 fs time resolution and diffraction-limited spatial resolution.
Optical manipulation of materials
We use femtosecond laser pulses as an active tuning knob to probe elusive structure-property relationships in emerging materials and control their properties out of equilibrium. To this end, we combine ultrafast excitation (electronic or vibrational) with time-resolved absorption, luminescence and Raman measurements of materials at controlled environments. Our optical setups are flexible, well integrated, and routinely modified to engage with different measurements.
We gratefully acknowledge the following funding agencies for supporting our work.