Controlling the Quantum World The Science of Atoms, Molecules, and Photons (2007) / Chapter Skim
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4 Extreme Light
4 Extreme Light
Pages 73-97
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From page 73... ...
EXTREME X-RAY LASER LIGHT in the 20th century, short-wavelength light from synchrotrons or lasers in the ultraviolet or x-ray regimes enabled the visualization of the crystalline structure of proteins, the imaging of cells in three dimensions, the study of the electronic structure of superconducting materials, and the creation of highly excited states of atoms, molecules, and clusters. this work included the use of x rays to uncover the double-helix structure of DNA.
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From page 74... ...
Advanced x-ray sources will be developed through the combined efforts of scientists in universities, national laboratories, and industry. their scale will range from tabletop systems designed for very short pulses of soft x rays to large national
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From page 75... ...
Furthermore, the high-harmonic x-ray emission process itself is extremely brief, much shorter than the laser pulse duration. this means that by using very short laser pulses, 5 femtoseconds or less, it is possible to create x-ray beams with ultrashort, subfemtosecond (or attosecond)
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From page 76... ...
at Brookhaven National Laboratory; Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory; Advanced Photon Source (APS)
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From page 77... ...
To get a feel for what this means in practice: Dental x rays and radiation therapy x rays are hard; solar flares produce both hard and soft x rays; and the gaseous plasmas in arc lamps and welders produce mainly soft x rays. These light sources may be used for next-generation microlithography, where the energy needs to be absorbed in a very precise nanopattern in a very thin layer (see Figure 4-2-1)
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From page 78... ...
controlling Quantum world 8 the FIGURE 4-2 High-repetition-rate, tabletop soft x-ray lasers may become workhorses in next-generation photolithography, metrology, and other nanotechnology applications. Upper charts show the soft x-ray emissions from the tabletop x-ray laser at Colorado State University, shown in the lower picture.
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From page 79... ...
Christov, 2005, Extreme nonlinear optics: Coherent x rays from lasers, Physics Today 58 (3)
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From page 80... ...
sources that combine the benefits of different kinds compact x-ray sources have just been demonstrated, paving the way for further advances in extreme light. EXTREME X-RAY LIGHT SOURCES AND THE WORLD'S FIRST X-RAY LASER FACILITY the largest x-ray laser currently under construction in the United States and indeed the world, and the first scientific user facility for x-ray lasers, is the Linac coherent Light Source (LcLS)
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From page 81... ...
These x-ray sources, however, are based on electron storage rings and are therefore constrained in the type of x-ray radiation that can be produced. For example, x rays from today's typical third-generation x-ray sources have relatively long pulse durations, ranging from tens to hundreds of picoseconds.
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From page 82... ...
AMO Contributions to Single-Molecule Imaging Several fundamental challenges of time-resolved, single-molecule imaging in volve AMo physics. the very high radiation damage to a single biomolecule from a focused x-ray laser beam of some trillion x rays is far beyond anything known in protein crystallography.
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. What has been realized recently is that if extremely short x-ray laser pulses (tens of femtoseconds or less)
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From page 84... ...
light. Inner Shell Atomic Multiple Ionization the LcLS x-ray laser beam will be the first x-ray source in history to be able to generate the same extreme focused powers that can be accessed by current
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. SOURCE: Keith Hodgson, Stanford Synchrotron Radiation Laboratory.
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the most incoherent light comes from thermal sources like the sun. the most coherent light comes from lasers, and the new extreme light sources -- both tabletop and large facilities such as the LcLS -- produce the most coherent x rays ever made.
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From page 87... ...
ULTRAINTENSE LASERS: USING EXTREME LIGHT SOURCES TO HARNESS EXTREME STATES OF MATTER think of a laser beam focused onto a spot on a solid surface smaller than the diameter of a human hair. As we begin to increase the laser pulse energy, we first vaporize the spot to create a crater.
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From page 88... ...
1024 2 Elaser~ mc e At 1019 W/cm2 , optical laser fields 1020 drive electrons to relativistic speeds 1018 Elaser~ e2 At 1016 W/cm2, intensity corresponds to a0 atomic strength laser fields 1015 Chirped pulse amplification 1015 mode-locking 1010 Q-switching 1960 1970 1980 1990 2000 2010 FIGURE 4-7 The exponential increase in achievable laser intensity over the 50-year history of the laser. 4-7 Redrawn
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From page 89... ...
the scientific opportunities enabled by ultraintense lasers to understand, control, and use high-energy-density states of matter are diverse and very exciting. At the ultrahigh intensities now achievable with the current generation of lasers, enormous electric fields can accelerate electrons to very high energy.
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From page 90... ...
Much like a surfer on a wave, accelerating particles move forward on the wave and can ultimately even overtake the laser pulse, thus terminating the acceleration and limiting the energy gain. The next decade will realize gigaelectronvolt- and teraelectronvolt-class electron beams using next generation lasers, lower plasma densities, and longer guiding distances for the laser.
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From page 91... ...
in addition, these HeD plasmas may be controlled for application in many important technological problems, ranging from accelerating particles to high velocity to developing new and precise imaging technologies.3 Ultraintense lasers provide a controlled means for creating and studying these 3For a review of opportunities in HeD physics, see NRc, Frontiers in High Energy Density Physics: The X-Games of Contemporary Science, Washington, D.c.: the National Academies Press (2003) , available at |
From page 92... ...
Laser technology has advanced in recent years to the point where light pulses with peak powers of tens to thousands of trillions of watts are possible. these ultraintense lasers can essentially concentrate the equivalent power of the entire electrical grid of the United States onto a spot only a tenth of a human hair in diameter (though only for an instant)
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From page 93... ...
Accelerating Particles with Light the preceding sections have just described how the enormous electric fields present in the plasmas created by superintense lasers can accelerate electron beams to multi-GeV energies within a few centimeters. The Energy Frontier the high-energy frontier for particle physics will require particle energies well in excess of 1 teV for studies of fundamental properties of matter.
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From page 94... ...
As discussed above, such a compact source of ultraintense, femtosecond x rays would enable many experiments involving molecular, atomic, and biological systems on the natural timescales of atomic motion. The Intensity Frontier -- Sparking the Vacuum A third frontier is the intensity frontier, where electric field strengths in excess of the Schwinger critical field limit are generated.
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From page 95... ...
The Fastest Pulse: Complementarity Between Extreme Light and Extreme Particle Beam Collisions A fully stripped uranium nucleus passing rapidly through a high-Z atom at a distance of one hundredth of a typical atomic diameter from the nucleus of the target atom applies to the inner shell electrons of the atom an electric field a million times greater than the field that an electron in the ground state of a hydrogen atom would experience. if this ion is moving at relativistic speeds (see Box 4-6)
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From page 96... ...
In situ spectroscopy can also be performed using resonant electron capture (dielectronic recombination) in the electron cooler in the ring, with a precision easily capable of revealing the QED contributions to the energies.
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From page 97... ...
extreme light FIGURE 4-6-1 Planned GSI facilities (shown in red)
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