Ultrashort laser pulses are an area of research for which TU Wien has been highly regarded internationally for some years. At the Photonics Institute in the Faculty of Electrical Engineering and Information Technology, they have continued to succeed in enhancing laser technology and gaining new insights into the interaction between light and materials. This research unit is now receiving additional support from the European Research Council: Professor Andrius Baltuska has received an "ERC Starting Grant" for his project, in which he seeks to develop methods to customise ultrashort laser pulses and endow them with the required shape. To achieve this, light waves of various wavelengths need to be superimposed on one another - with a precision of around one billionth of a billionth of a second.
We know from acoustics how waves are superimposed: when various musical instruments are playing the same note, they produce sound waves with the same basic wavelength. Nevertheless, they all sound different. This is because each musical instrument also produces even higher frequencies in addition to the basic tone. A number of sound waves are thus produced simultaneously with different pitches, which merge to form a combined wave with a complex waveform - and our brain perceives the different waveforms as different tones.
Inconceivably short timescales
Professor Baltuska's research seeks to do something similar with the light waves from short laser pulses. Andrius Baltuska is convinced that: "If we succeed in precisely controlling the superimposition of light pulses of different wavelengths, customised waveforms can be generated." The timescale we are talking about here is unimaginably short: the duration of light pulses is in the region of attoseconds. One attosecond (10^-18 seconds) is one billionth of a billionth of a second. An attosecond is to one second, what a second is to the age of the universe. With terms from our everyday experience, we can barely imagine an attosecond. Not even a supersonic aircraft can travel at the speed of an attosecond, which equates to the diameter of an atomic nucleus. However, many processes at atomic and molecular level run according to such infinitesimally small timescales - to explore these processes, ultrashort laser pulses have become an indispensable tool.
Customising wave pulses
In recent years, the field of attosecond research has expanded rapidly. Various research groups around the world are now able to work with these extremely short laser pulses. "Customising laser pulses and specifically forming them is now the logical next step," believes Andrius Baltuska. "With our equipment and the expertise we have established in our working group, we are in the excellent position to be the first to break new ground in this field," says a confident Baltuska. There have been some initial preliminary studies at the Photonics Institute - in principle it should be possible to customise the forms of light pulses. With the financial support of the ERC grant, the idea can now actually be implemented. With short laser pulses, electrons can be torn out of atoms. The electron can then return to the atom and the energy absorbed can be emitted in the form of an even shorter laser pulse. "We are seeking to significantly improve processes like this, by specifically optimising the shape of laser pulses for this purpose," says a hopeful Andrius Baltuska.
Webseite of the Photonics group at TU Wien: www.photonik.tuwien.ac.at, opens an external URL in a new window
Prof. Andrius Baltuska
Institute of Photonics
Gusshausstraße 25-29, 1040 Vienna
Phone: +43 1 58801 38749
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Operngasse 11, 1040 Vienna
Phone: +43 1 58801 41027