Optical Physics

Jun Ye Elected to the National Academy of Sciences

05/03/2011

On May 3, the National Academy of Sciences announced the selection of Jun Ye as one of 72 new members and 18 foreign associates. Ye is a Fellow of JILA and a Fellow of NIST, the National Institute of Standards and Technology. He is also an adjoint professor in the Department of Physics at the University of Colorado at Boulder. Ye and his scientific colleagues were recognized for their distinguished and ongoing achievements in original research. The new additions bring the total number of active members to 2,113 and the total number of foreign associates to 418. Read more »

Steven Cundiff Receives William F. Meggers Award

04/15/2011

JILA Fellow Steven Cundiff has received the Optical Society of America’s 2011 William F. Meggers Award. The award recognizes outstanding work in the study and measurement of the interactions between light and matter (spectroscopy). The award cited Cundiff’s contributions to the field of ultrafast spectroscopy of semiconductors, including multidimensional Fourier transform techniques, and to the development of femtosecond frequency comb technology. Read more »

The Quantum Control Room

Collisions between ultracold KRb molecules can suppressed a hundredfold in two-d

In 2008, the Ye and Jin groups succeeded in making ultracold potassium-rubidium (KRb) molecules in their ground state (See “Redefining Chemistry at JILA” in the Spring 2010 issue of JILA Light & Matter). Their next goal was to figure out how to precisely control chemical reactions of these ultracold polar molecules by manipulating the quantum states of the reactants. But first the researchers had to discover how to calm those reactions down enough to study them. Read more »

The Fickle Finger of Fate

This density plot shows vortices forming in a dipolar BEC being tickled by a las

Putting the brakes on a superfluid dipolar Bose-Einstein condensate (BEC) just got a whole lot more interesting. Last year, the Bohn theory group explored what would occur in a dipolar BEC when a laser probe — think of it like a finger — tickled a BEC just hard enough to excite a roton. (see JILA Light & Matter, Summer 2010).Read more »

Jun Ye

Jun Ye was born in Shanghai, China, in 1967. His father was a naval officer who later pursued a career in business. His mother was an environmental scientist and city official who controlled funding for environmental protection. While his parents were busy with their careers, Ye grew up in Shaoxing, a city about 200 km south of Shanghai. He was raised by his father’s mother, E-Gui Jin, who placed such a high value on education that he would dedicate his Ph.D. Read more »

Strontium Clock Performance Skyrockets

The accuracy of the Ye group’s neutral Sr optical atomic clock has significantly

Quantum Paradox Derails Unwanted Collisions Read more »

Jun Ye wins 2011 Frew Fellowship

02/03/2011

Jun Ye has been selected as the 2011 Frew Fellow by the Australian Academy of Science. Ye will present the Frew Lecture at the Australasian Conference on Optics, Lasers, and Spectroscopy (ACOLS), which is incorporated in the International Electronic Conference/CLEO Pacific Rim 2011 meeting to be held in Sydney, Australia, from August 29 to September 1, 2011. In addition to presenting the Frew lecture on a topic of his choice, Ye will visit universities and research institutions in different Australian cities. Read more »

The Long Goodbye

Experimental measurements showing how the density of the electrons that bind the

The dance of electrons as a bromine molecule (Br₂) separates into two atoms is intricate and complex. The process of breaking up takes far longer than expected (~150 vs 85 fs) because the cloud of electrons that bind atoms together in a molecule behaves as if it were still surrounding a molecule until the last possible moment — when the atomic fragments are about twice the normal distance apart (~.55 nm). At this point, there’s simply not enough energy left in the system to hold the molecule together. Read more »

A Rainbow of X-Rays

Henry Kapteyn and Margaret Murnane in their laboratory at JILA.

Many people who have seen a green laser pointer “know” that laser light is a single pure color. But this idea doesn’t hold true for all lasers. Special lasers called femtosecond lasers can produce rainbows of tens, hundreds, or even millions of pure colors. These rainbows can include colors with wavelengths (in the infrared) that are too long for people to see and colors with wavelengths (in the ultraviolet) that are too short for people to see. Read more »

Rainbows of Soft X-Rays

Cover of Physical Review Letters showing results of a double-slit experiment dem

Artist’s impression of the coherent-light upconverter used in the Kapteyn/Murnan

The vision of a tabletop x-ray laser has taken a giant step into reality, thanks to Tenio Popmintchev, Ming-Chang Chen and their colleagues in the Kapteyn/Murnane group. By focusing a femtosecond laser into a gas, Popmintchev and Chen generated many colors of x-rays at once, in a band that stretched from the extreme ultraviolet into the soft x-ray region of the electromagnetic spectrum, spanning wavelengths of ranging from about 6 to 2.5 nm. This broad x-ray band has so many different colors that all the waves can be added together to form the shortest strobe light in existence. Read more »