An optical trap is a scientific tool that uses focused laser beams to hold and manipulate small particles, such as cells or molecules. The laser light creates a gradient of force that can attract or repel these particles, allowing researchers to study their properties and behaviors in a controlled environment. This technique is widely used in fields like biophysics and nanotechnology. By trapping particles, scientists can perform precise measurements and experiments, such as observing the movement of DNA or the interactions between proteins. Optical traps have advanced our understanding of microscopic processes in biology and materials science.