This project concerns the methods of trapping, sorting, mixing, and aligning nano- and micro-scale dielectric particles of arbitrary shape using electromagnetic fields within microfluidic environments. We are currently approaching this on two fronts:
Motivation for Approach
Several other prominent research groups and companies are engaged in similar projects implementing spatial light modulators and holographic optical trapping. Our approach (in theory and experiment) complements the need for specific optical elements, and instead relies on simple holography to form the optical fields of interest.
Such an approach holds several potential advantages: on-the-fly alteration of the interference field to any arbitrary pattern, a wavelength-independent manipulation system, an area of impact limited only by the primary laser power, and, because no specialty optical elements are required, a lower overall cost.
Our mathematical model will allow designers of optical trapping and manipulation systems access to several novel techniques, or "knobs to turn". Perhaps most importantly, because many particles of interest are not perfect spheres, our model accepts particles of arbitrary shape (e.g., blood and tissue cells, nanowires, microrotors), and finds that they behave much differently in an optofluidic system.
Our physical system will not only provide validity to our mathematical model, but will also allow for non-invasive and highly dynamic particle manipulation, alignment, mixing, sorting, etc. Due to our interest in sorting living cells, we currently employ infrared light at 1064nm. However, our system is easily tuned for a wide range of optical wavelengths.