Making perfectly controlled arrays of molecules at rest

Svetlana Kotochigova

Since their invention in the early 1970s, optical tweezers have evolved from enabling simple manipulation to applying calibrated forces on—and measuring nanometer-level displacements of—optically trapped objects. Optical tweezers use laser light to create a force trap that can hold nanometer- to micrometer-sized dielectric objects (1). They can noninvasively manipulate objects such as biological cells in water, as well as apply piconewton forces to single molecules in solution or in free space. Combining these optical traps with laser cooling, which stops atoms and small molecules from moving in free space at ultracold temperatures, allows for precision measurements. On page 1156 of this issue, Anderegg et al. (2) created an array of optical tweezers filled with ultracold calcium monofluoride (CaF) molecules. Individual molecules were brought together by tweezer traps, enabling their interaction. Such unprecedented control should allow high-precision observations of molecular collisions and could provide insight into specific chemical reactions.

DOI