Matthew Berg (right), an assistant professor of physics and astronomy at Mississippi State, and graduate student Nava Subedi, from Nepal, lead an optical experiment to image small particles using multicolor digital holography. The technique uses laser light at several wavelengths and a color sensor to record the complex interference pattern produced by light interacting with a particle, such as pollen and mineral dust particles. The purpose of the experiment is to lay the foundation for the eventual development of a portable sensor that will characterize the particles present in the atmosphere in urban and agricultural environments.