ABSTRACT
Ever since its first demonstration in the 1970s by Ashkin and coworkers,1,2 optical trapping has become a mainstream technology extensively used for confinement and manipulation of micro-and nanoscale objects. In its most popular form, an optical trap, or “optical tweezers,” is created by a single laser beam tightly focused through a high numerical aperture (NA) microscope objective. This relatively simple configuration is capable of exerting picoNewton level forces in a non-contact manner and simultaneously measuring the trapped particle displacement with nanometer level precision, thereby enabling a plethora of applications in cell biology, immunology, rheology, biophysics, and colloid science.
