A Brimrose Corporation of America acousto-optic modulator (AOM) is now being used by NASA as part of a new facility known as the Cold Atom Laboratory (CAL) on the International Space Station (ISS). Fiber-coupled version of the acousto-optic modulator. Courtesy of Brimrose. The Cold Atom Laboratory was developed at NASA’s Jet Propulsion Laboratory and already has begun operating on the ISS. It will provide scientists with an improved set of tools for probing the realm of quantum mechanics. The AOM is a fiber-coupled, solid-state device that can tune laser light to very specific frequencies while switching on and off in less than 100 ns. It is the key component inside CAL for manipulating the atoms for interferometry. The CAL facility will produce clouds of ultracooled atoms called Bose-Einstein condensates (BEC). These are chilled to a fraction of a degree above absolute zero, or even colder than the average temperature of deep space. The atoms in a BEC demonstrate quantum characteristics at relatively large size scales, allowing researchers to explore the domain with greater understanding. To reach these ultracold temperatures, the CAL uses a three-step process. First, lasers are used to corral the atoms and slow them down, stealing their energy and reducing the temperature to approximately 100 μK. This step is completed with a device called a magneto-optical trap. Second, the cooled atoms are held in the magnetic trap that causes the warmest atoms in the cloud to separate from the cooler atoms; radio waves then push the warm atoms away, reducing the cloud’s overall temperature to less than 1 μK. Third, the cloud’s natural expansion causes the temperature to drop further (this is called adiabatic expansion) into the 100 pK range. In one year, the CAL instrument is expected to be fitted by astronauts with a new atom-trapping cell currently being designed to deliver the Brimrose AOM light pulses to the atoms.