Research Highlights

Jason Jones, Kevin Moll, Mike Thorpe, and Jun Ye have generated the world's first precise frequency comb in the extreme ultraviolet (EUV) using a combination of an ultrafast mode-locked laser and a precision high-finesse optical cavity. The EUV frequency comb consists of regularly spaced sharp lines that extend into the EUV region of the electromagnetic spectrum.

Andrew Hamilton and Jason Lisle, who received his Ph.D. in astrophysical and planetary sciences in 2004, have proposed a new model for the flow of matter into stationary and rotating black holes. In their "river model of black holes," space flows like a river through a flat background, while objects (like light rays) that move through the river abide by the rules of special relativity. 

Three years ago Jun Ye decided to apply an old idea for amplifying and stabilizing continuous-wave (cw) lasers to state-of-the-art ultrafast lasers. In 2002, Jason Jones, a postdoctoral fellow with Jun, analyzed whether the build-up cavities used to amplify cw laser outputs could be modified to work with ultrafast, mode-locked lasers. His detailed calculations suggested that it would be possible but technically demanding.

A high-powered JILA collaboration led by JILA Fellows Jun Ye and Chris Greene is making important progress toward developing an ultrastable, high-accuracy optical atomic clock. The new optical clock design will use a variety of laser sources including a femtosecond comb and a diode laser stabilized with an optical cavity, which, in turn, is locked to a narrow energy level transition in ultracold strontium atoms.

Imagine high-school or college students so excited about physics they can hardly wait to get to class every day and learn more about how the world works. Fellow Carl Wieman recently offered cogent suggestions to new physics teachers on coming closer to this ideal. First, he recommended starting with research on how people learn physics and paying particular attention to the concept of "cognitive load." This concept, which posits that people can only process about seven ideas in short-term working memory, sets clear limits on how much information can be effectively introduced in a single lesson (or scientific talk).

Pete Roos, Tara Fortier, Xiaoqin Li, Ryan Smith, Jessica Pipis, and Steve Cundiff are using a phase-controlled mode-locked laser to control quantum processes in semiconductors. Semiconductors are capable of producing electrical currents from light (and vice-versa) and are the basis for a wide variety of optoelectronic devices, including photodiodes, light-emitting diodes, and solar cells.

It’s been more than 40 years since Russian theoretical physicist Vitaly Efimov predicted a strange form of matter called the Efimov state in 1970. In these strange states, three atoms can stick together in an infinite number of new quantum states, even though any two of the atoms can’t even form a molecule.