optics

In an effort to improve atomic clocks, JQI Fellow Kartik Srinivasan and his colleagues have been exploring how light is altered as it races repeatedly around a minuscule track on a chip. In an article in Nature, they describe a new way to use the devices to make precision measurements of light. The new technique might eliminate the need for several large, energy-hungry components in next-generation optical atomic clocks and other metrology tasks.

Optical fibers are hair-like threads of glass used to guide light. Fibers of exceptional purity have proved an excellent way of sending information over long distances and are the foundation of modern telecommunication systems. JQI researchers in collaboration with scientists from the Naval Research Laboratory have developed a new technique for visualizing light propagation through an optical nanofiber, detailed in a recent Optica paper. The result is a non-invasive measurement of the fiber size and shape and a real-time view of how light fields evolve along the nanofiber. Direct measurement of the fields in and around an optical nanofiber offers insight into how light propagates in these systems and paves the way for engineering customized evanescent atom traps.  

Color is strange, mainly due to perception. Setting aside complex brain processes, what we see is the result of light absorption, emission, and reflection. Trees appear green because atoms inside the leaves are emitting and/or reflecting green photons. Semiconductor LED brake lights emit single color light when electrical current passes through the devices.