Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Solid-state photonics goes extreme ultraviolet

28.05.2015

Using ultrashort laser pulses, scientists in Max Planck Institute of Quantum Optics have demonstrated the emission of extreme ultraviolet radiation from thin dielectric films and have investigated the underlying mechanisms.

In 1961, only shortly after the invention of the first laser, scientists exposed silicon dioxide crystals (also known as quartz) to an intense ruby laser to double its frequency, i.e., to change its colour from the visible to the ultraviolet, marking the advent of nonlinear optics and photonics.


Ultrafast lasers drive the motion of electrons inside silicon dioxide to generate extreme ultraviolet radiation.

(Graphic: Christian Hackenberger)

Now, researchers around Dr. Eleftherios Goulielmakis of the Attoelectronics Research Group at the Max Planck Institute of Quantum Optics in Garching, flashed an intense ultrashort laser pulse on thin films of the same material as in the mentioned pioneering experiment, and succeeded to convert laser light into radiation having a frequency more than 20 times higher than that of the laser, i.e., into the extreme ultraviolet range of the spectrum.

The laser pulses used comprised merely of a single oscillation of their wave cycle and allowed the scientists to drive the motion of electrons inside the crystal lattice extremely fast. As the electrons of the material bounced on the lattice potential formed by the atoms in the crystal, they radiate and thus convert the energy taken up by the laser light into extreme ultraviolet radiation. The experiments pave the way towards new solid-based photonic devices. Because the motion of the electrons driven by the laser pulse probes the properties of the solid, measurements of the emitted radiation lead to a deeper understanding of the structure and the inner workings of solids. (Nature, 28 May 2015)

Nonlinear optics and its wide range of modern applications in fundamental science, laser technology, telecommunications and medicine rely on the conversion of light from one colour to another, a process which takes place when an intense laser interacts with matter. Such processes allow one to generate laser-like radiation of frequencies (colour), which cannot be directly produced in lasers and hence to exploit it for new applications.

For more than two decades scientists have utilized very intense lasers to drive the motion of electrons in atoms or molecules in the gas phase such as to produce radiation in the extreme ultraviolet or even the x-ray part of the spectrum. “In condensed phase media — which comprise the basic pillar of modern fundamental and practical photonic applications — things are much more challenging”, says Goulielmakis, leader of the research group.

Solids cannot stand intense lasers without being damaged, and even worse, the fast vibrating atoms inside a solid randomly collide with the laser-driven electrons preventing the generation of coherent, laser-like radiation. By using extremely fast laser pulses (typically less than 2 femtoseconds) — so fast as to comprise only a single oscillation of a light wave generated by a “so-called” light field synthesizer — the MPQ scientists succeeded to sidestep these challenges. “Matter can stand intense field when illuminated for a very short time to produce extreme ultraviolet, and atoms merely move within this short time scale”, says Tran Trung Luu, scientist in the team.

But the MPQ scientists didn’t stop there. “We exploited the emitted EUV radiation to unveil information about the structure —more specifically the conduction band dispersion— of the solid which was earlier inaccessible to solid state-spectroscopies”, Goulielmakis points out. Being exposed to the optical fields the electrons get a kick from the valence band to the conduction band where they are accelerated by the laser field. “As the electrons move, they “feel” the surrounding structure of the solid, and this information is embodied in the emitted radiation”, says Manish Garg, a scientist in the team.

But how fast do electrons oscillate to produce extreme ultraviolet radiation in a solid? This is revealed by the frequency of the emitted radiation and the theoretical interpretation of the experiments. “We have a strong indication that the laser pulses force the electrons to perform extremely fast oscillations of tens of Petahertz (1015 Hz) frequencies inside the crystal,” Goulielmakis explains. “In fact, this is the fastest electric current ever generated in a solid, and the emitted radiation from these oscillations allow us to peer into the dynamics of this extremely fast motion.”

By manipulating the waveform of the laser pulses with the light field synthesizer, the scientists also succeeded to control these ultrafast electric currents inside the solid. “Our work opens up new routes for realizing light-based electronics operating at multi-PHz frequencies,” Dr. Goulielmakis resumes. [EG/OM]

Original publication:
T. T. Luu, M. Garg, S. Yu. Kruchinin, A. Moulet, M. Th. Hassan and E. Goulielmakis
Extreme Ultraviolet High-Harmonic Spectroscopy of Solids
Nature, 28 May, 2015, DOI: 10.1038/nature14456

Contact:
Dr. Eleftherios Goulielmakis
ERC Research Group Attoelectronics
Max Planck Institute of Quantum Optics
Laboratory for Attosecond Physics
Hans-Kopfermann-Str. 1, 85748 Garching, Germany
Phone: +49(0)89 / 32 905 -632 /Fax: -200
E-mail: Eleftherios.Goulielmakis@mpq.mpg.de
www.attoworld.de/goulielmakis-group

Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics
Hans-Kopfermann-Straße 1, 85748 Garching, Germany
Phone: +49 (0)89 / 32 905 -213
E-mail: olivia.meyer-streng@mpq.mpg.de

Weitere Informationen:

http://www.mpq.mpg.de

Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik

More articles from Physics and Astronomy:

nachricht Unraveling the nature of 'whistlers' from space in the lab
15.08.2018 | American Institute of Physics

nachricht Early opaque universe linked to galaxy scarcity
15.08.2018 | University of California - Riverside

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Unraveling the nature of 'whistlers' from space in the lab

15.08.2018 | Physics and Astronomy

Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide

15.08.2018 | Earth Sciences

Early opaque universe linked to galaxy scarcity

15.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>