Kapteyn

Henry Kapteyn Elected as a Member of the National Academy of Sciences

04/30/2013

Henry Kapteyn has been elected to membership in the National Academy of Sciences, the academy announced on April 30, 2013. Kapteyn joins seven other members of the JILA faculty as members of the academy. They include John Hall (1984), Carl Wieman (1995), Eric Cornell (2000), Margaret Murnane (2004), Deborah Jin (2005) and Jun Ye (2011). NIST Nobel Laureate Dave Wineland and CU Physics Professors Noel Clark and John Wahr are also academy members.Read more »

The Spider's Secrets

Graduate student Dan Hickstein (Kapteyn/Murnane group) recently investigated the behavior of electrons ripped from atoms and molecules by intense infrared laser pulses. Read more »

X-ray Visionaries

Caption: Interference pattern of laser-like x-rays made in the Kapteyn/Murnane l

The Kapteyn/Murnane group had the idea that it might be possible to produce bright, laser-like beams of x-rays using an ultrafast laser that fits on a small optics table. Read more »

The Secret Life of Magnets

A tabletop x-ray laser is “watching” iron spins (white) that have just been

The Kapteyn/Murnane group and scientists from NIST Boulder and Germany have figured out how the interaction of an ultrafast laser with a metal alloy of iron and nickel destroys the metal’s magnetism. In a recent experiment, the researchers were able to observe how individual bits of quantum mechanical magnetization known as “spin” behaved after the metal was heated with the laser. The researchers included newly minted Ph. D. Read more »

Designer Lasers

Margaret Murnane and Henry Kapteyn in their laboratory at JILA.

Extreme frequency upconverter of coherent light for transforming infrared laser

Life in the fast lane – developing the world’s fastest laserRead more »

Optical Frequency Combs

Extreme ultraviolet (XUV) frequency comb.

Titanium sapphire crystal in an optical frequency comb.

JILA scientists John Hall , Steve Cundiff , and Jun Ye are world leaders in research on frequency combs. Combs are spectra consisting of hundreds of thousands of evenly spaced sharp spectral lines (colors) produced by extremely stable ultrafast lasers. The line spacing in these spectra is so exact that combs can be used to precisely measure the frequency of hundreds of thousands of discreet colors of light. These new rulers of light are now providing measurement precision that was unheard of until 2003. Read more »

Reactions on Demand

By adjusting three colors of light (red IR photons and two higher-energy blue an

Predrag Ranitovic dreams of controlling chemical reactions with ultrafast lasers. Now he and his colleagues in the Kapteyn/Murnane group are one step closer to bringing this dream into reality. The group recently used a femtosecond infrared (IR) laser and two extreme ultraviolet (XUV) harmonics created by the same laser to either ionize helium atoms or prevent ionization, depending on experimental conditions. 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 »