Optical Tweezers

An ``optical tweezers'' device was constructed using an obsolete microscope and off-the shelf parts. This apparatus is intended to serve as a demonstration of the forces in a single beam,~gradient radiation pressure laser trap for use in the Texas Lutheran University (TLU) advanced lab course. At the start of this project, the tool was disassembled and scavenged for parts for other experiments. Once assembled, the challenge of a low-cost sample illumination mechanism became a roadblock to imaging the particles for trapping. The field of view~is on the order of only a few microns,~such that illuminating the sample without~imaging other artifacts is~not a trivial task.~In this project, we have developed an innovative light source that combines an ultra-low cost integrating sphere and an off the shelf super bright LED lamp. The light source design and construction, including integration of optics using custom, 3D-printed coupling parts will be discussed.