1. Quantitative Biomedical Imaging with Nonlinear Optical Microscopy

We employ multimodal nonlinear microscopy tools (CARS/SHG/TPEF) to quantitatively image biological tissues and structures. We are currently interested in the following topics:

• Following the process of skin optical clearing with dimethyl sulfoxide. [paper]
• Quantitatively determine the diffusion of selected chemicals in human hair.
• Quatitative mapping of lipid accumulation in athermomas in an ApoE- mouse model

2. Nonlinear Imaging of Nanostructures

We are interested in characterizing the nonlinear optical properties of nanostructures. The third order optical response of nano-compounds is explored by detecting the coherent anti-Stokes electronic signatures of such systems. We are currently working on the following projects:

• Imaging nonlinear response of plasmon resonances in gold and silver nanowires. [paper]
• Visualizing carbon nanotubes through electronic coherent anti-Stokes generation. [paper]

We use focus-engineered CARS techniques to improve contrast in nonlinear microscopy. By phase shaping the incident beams, the CARS phase matching conditions in the focal volume can be controlled. Precise control of the focal beams offers multiple opportunities for improving the imaging capabilities. We develop and utilize these approaches in the following projects:

• Differential nonlinear microscopy for CARS background suppression in biological imaging
• Imaging with multi-dimensional differential contrast [paper]
• Focus-engineering for imaging with higher spatial resolution

Potma Labs, Department of Chemistry, Natural Sciences II, University of California, Irvine, CA 92697