Current OSL Research Projects

Our research is mostly concentrated on the development of novel optical techniques for extracting relevant information in two or three spatial dimensions in highly scattering materials such as biological tissue. In such materials, light that would travel in a straight line in clear materials is instead scattered into random directions. Such scattering causes normal imaging techniques to fail. Nevertheless absorption is often low and light may travel a good distance before being absorbed. We must either detect only the small amount of unscattered light or find ways to obtain useful information from the highly scattered light. The principles are very similar for imaging through skin in the body (at distances of hundreds of microns to millimeters) and imaging through adverse weather in the atmosphere (at distances of meters to kilometers).

Structured Illumination Microscopy

Structured illumination microscopy allows us to reject the highly scattered light and work with that which is unscattered or weakly scattered. An illumination pattern is focused into the material at the desired depth. The modulation pattern is diminished at out-of-focus planes, and for light that is strongly scattered. By processing the detected image, we can use the modulation as a tag to select light from a specific plane. Structured illumination thus enables us to see into skin much deeper than is possible with wide-field microscopy.

Updated December 2017

Light and Sound

Another technique for tagging light is the use of ultrasound. The focused ultrasound produces subtle changes in the speckle pattern of scattered laser light. Detecting these changes ensures that we are detecting only light that passed through the focus of the ultrasound beam. By scanning the ultrasound beam, we can construct an image.

Updated December 2017


Returning to Chuck's roots in the field of laser radar, we have been investigating the propagation of light in adverse weather, both experimentally and computationally. We can improve the images collected by scanning lidars through better understanding of the scattering properties of the atmosphere.

Updated October 2018

Some of Our Earlier Projects

Mostly Experimental

Step-wise Excitation of Melanin SHG Corneal Collagen Acousto-Photonic Imaging
Embroyo Cell Counting Dual Wedge Confocal Confocal Reflectance Pupil Engineering
CRM with Articulated Arm Theta Line Scanner Photothermal Microscopy
Photoacoustic Schlieren Nanoparticles in Skin Axotomy Calcium Imaging

Mostly Computational

Phase Conjugation Model for Phase Microscopy Fuel Cells
Lung Tomography FTDT Skin Model FDTD for Oct in Lung