Yingzhong Ma

Staff Research Scientist

Yingzhong received his Ph.D. in physical chemistry from Umeå University, Sweden, under the supervision of Prof. Tomas Gillbro in 1999. The research during his stay in this Nordic country was focused on an ultrafast optical spectroscopic study of electronic excited-state energy and electron transfer processes in purple and green photosynthetic bacteria. He then joined the group of Prof. Alfred Holzwarth at the Max-Planck Institute for Radiation Chemistry (now the Max Planck Institute for Chemical Energy Conversion), Germany, where his work was centered on time-resolved spectroscopic characterization of artificial photosynthetic systems. Yingzhong moved to California in 2000 where he had an extended stay in the group of Prof. Graham Fleming, University of California, Berkeley. There he was given the opportunities of exploring several challenging questions, such as the physical mechanisms underlying the nonphotochemical quenching process that regulates photosynthetic light harvesting in plants as a protective response to changes in excessive incident light intensity, ultrafast electronic excited-state phenomena in semiconducting single- and doubled-walled carbon nanotubes, and laser-induced drug delivery, etc. These studies involved use of a suite of ultrafast laser spectroscopic tools, including two- and three-pulse photon echo, heterodyne-detected transient grating and transient absorption spectroscopies. In 2009, Yingzhong joined the Chemical Sciences Division as a staff member, where he initiated a systematic ultrafast spectroscopy research at ORNL, with specific focuses on understanding fundamental energy and charge transport phenomena with high spatial, spectral and temporal resolution. His research has since span from low-dimensional nanostructures, molecular systems to polymeric and semiconducting photovoltaic materials. In recent years, this research has seen major advances with the addition of several femtosecond laser systems, which are capable of producing pulse energies spanning over six orders of magnitude and very broad tunability ranging from UV to mid-infrared spectral regions, along with the development of a series of ultrafast optical spectroscopic and microscopic approaches for directly probing electronic, vibrational and thermal processes in both bulk systems and interfaces.

Specialized Equipment

1 kHz and 250 kHz femtosecond Ti:Sapphire regenerative amplifiers in combination with their associated visible and infrared optical parametric amplifiers as well as frequency mixers, which enable to routinely generate 50 fs laser pulses with high pulse...