Credit: NIST
Illustration of a new optical system to miniaturize the laser cooling of atoms, a key step towards cooling atoms on a microchip. A beam of laser light is launched from a photonic integrated circuit (PIC), aided by an element called an extreme mode converter (EMC) that greatly expands the beam. The beam then strikes a carefully engineered, ultrathin film known as a metasurface (MS), which is studded with tiny pillars that further expand and shape the beam. The beam is diffracted from a grating chip to form multiple overlapping laser beams inside a vacuum chamber. The combination of laser beams and a magnetic field efficiently cools and traps a large collection of gaseous atoms in a magneto-optical trap (MOT).
It’s cool to be small. Scientists at the National Institute of Standards and Technology (NIST) have miniaturized the optical components required to cool atoms down to a few thousandths of a degree above absolute zero, the first step in employing them on microchips to drive a new generation of super-accurate atomic clocks, enable navigation without GPS, and simulate quantum systems.
Cooling atoms is equivalent to slowing them down, which makes them a lot easier to study. At room temperature, atoms whiz through the air at nearly the speed of sound, some 343 meters per second. The rapid, randomly moving atoms have only fleeting interactions with other particles, and their motion can make it difficult to measure transitions between atomic energy levels. When atoms slow to a crawl — about 0.1 meters per second — researchers can measure the particles’ energy transitions and other quantum properties accurately enough to use as reference standards in a myriad of navigation and other devices.
For more than two decades, scientists have cooled atoms by bombarding them with laser li ..
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