News Center

Surprising Control over Photoelectrons from a Topological Insulator

Electrons flowing swiftly across the surface of topological insulators (TIs) are “spin polarized,” their spin and momentum locked. This new way to control electron distribution in spintronic devices makes TIs a hot topic in materials science. Now Berkeley Lab scientists have discovered more surprises: contrary to assumptions, the spin polarization of photoemitted electrons from a topological insulator is wholly determined in three dimensions by the polarization of the incident light beam.

A Clock Einstein Would Have Loved

A very special clock that can measure time on the basis of the mass of a single atomic or even subatomic particle holds promise not only for ultraprecise measurements of mass and time, but also for such exotic applications as testing Einstein’s general theory of relativity, or the effects of gravity on antimatter. “We have

New Insight into an Intriguing State of Magnetism

Magnonics is an exciting extension of spintronics, promising novel ways of computing and storing magnetic data. What determines a material’s magnetic state is how electron spins are arranged (not everyday spin, but quantized angular momentum). If most of the spins point in the same direction, the material is ferromagnetic, like a refrigerator magnet. If half

Measuring Table-Top Accelerators’ State-of-the-Art Beams

“Slicing through the electron beam” is the second installment of a two-part feature about new techniques to test beam quality in laser plasma accelerators, including the metric known as slice-energy spread. As Berkeley Lab accelerator scientists meet the challenges of measuring extraordinarily short pulses in a complex environment, the approaching advent of the one-meter-long, 10-billion-electron-volt Berkeley Lab Laser Accelerator (BELLA) brings the promise of “table-top accelerators” closer to realization.

State-of-the-Art Beams From Table-Top Accelerators

“Emittance” is the first subject in a two-part feature about novel methods devised by Berkeley Lab scientists to test the quality of hard-to-assess beams from laser plasma accelerators. These table-top accelerators propel electron pulses to high energies within a few centimeters, promising far less expensive future accelerators with far less environmental impact than today’s conventional machines.

Synchronized Lasers Measure How Light Changes Matter

How matter responds to light lies at the core of vision, photosynthesis, solar cells and light-emitting diodes, and many other fields of scientific and practical import. But until now, it hasn’t been possible to see just how light does it. Berkeley Lab scientists have used SLAC’s Linac Coherent Light for the first demonstration that x-ray and optical wave mixing reveals not only structure but evolving charge states on the atomic scale.

BELLA Laser Achieves World Record Power at One Pulse Per Second

The laser system for BELLA, the Berkeley Lab Laser Accelerator, recently delivered a petawatt of power – a quadrillion watts – in a pulse just 40 femtoseconds long – a quadrillionth of a second — at a rate of one pulse per second. No other laser system has achieved this peak power at this rapid pulse rate. BELLA’s laser should soon be driving electron beams to 10-billion-electron-volt energies in an accelerator just one meter long.

A New Tool to Attack the Mysteries of High-Temperature Superconductivity

Using ultrafast lasers, Berkeley Lab scientists have tackled the long-standing mystery of how Cooper pairs form in high-temperature superconductors. With pump and probe pulses spaced just trillionths of a second apart, the researchers used photoemission spectroscopy to map rapid changes in electronic states across the superconducting transition, revealing relationships of energy and momentum never seen before in these promising, but stubborn, complex materials.

APEX: At the Forefront of What’s Needed for the Next Generation of Light Sources

An extraordinary “front end” for the next generation of light sources is taking shape at Berkeley Lab’s Beam Test Facility. APEX, an electron gun that will produce a continuous beam of tight electron bunches at the unprecedented repetition rate of a million bunches a second, is well on the way to becoming the must-have source for superconducting linear accelerators to power future free electron lasers.

The Next Big Step Toward Atom-Specific Dynamical Chemistry

Chemists hope to understand precisely how electrical charges flow and different forms of energy move within molecules and across molecular boundaries. The most demanding experiments would identify specific atoms and track their correlated electronic states, but the facilities don’t exist yet. Berkeley Lab scientists are using powerful lasers to devise future light sources that can do the job.