12 attoseconds is the world record for shortest controllable time

May 12, 2010
Ultrashort light pulse with stabilized optical phase. An ultrashort laser pulse is comprised of a few of these oscillations. (red or blue curve). Black curves: field envelope of the pulse. Maximum field strength is obtained if the field maximum coincides with the pulse center. (red curve). The newly developed method stabilizes the field pattern of the pulse. Two zoom-ins visualize smallest temporal fluctuations previously demonstrated (green frame, laser stabilization, 100 attosecond jitter) in comparison to those demonstrated with the new method of direct field synthesis (yellow frame, 12 attoseconds jitter).

Lasers can now generate light pulses down to 100 attoseconds thereby enabling real-time measurements on ultrashort time scales that are inaccessible by any other methods. Scientist at the Max Born Institute for Nonlinear Optics and Short Time Spectroscopy (MBI) in Berlin, Germany have now demonstrated timing control with a residual uncertainty of 12 attoseconds. This constitutes a new world record for the shortest controllable time scale.

Light is an of very high frequency. In the visible domain, a single oscillation of the electric field only takes about 1200-2500 attoseconds. Consequently, an ultrashort pulse is comprised of a few of these oscillations. However, pulses from conventional short-pulse laser sources exhibit strong fluctuations of the positions of the field maximum relative to the pulse center. For maximum field strength, the center of the pulse has to coincide with a maximum of the electric field, as shown in Fig. 1 as a red curve. Consequently, methods have been developed to stabilize the position of the field maximum, i.e., the phase of the pulse.

Together with Vienna based laser manufacturer Femtolasers, MBI researchers in the group of Günter Steinmeyer have now developed a new method to control the phase of the pulse outside of the laser. In contrast to previous approaches, no manipulation inside the laser is necessary, which completely eliminates fluctuations of and pulse duration and guarantees a strongly improved long-term stability. Correction of the pulse phase relies on a so-called acousto-optic frequency shifter, which is directly driven by the measured signal. Dr. Steinmeyer is convinced: "This direct correction of the phase dramatically simplifies many experiments in attosecond physics and frequency metrology."

Previously, stabilization of the position of the field maxima was only possible with a precision of about 100 attoseconds (10-16 s, corresponding to 1/20 of the wavelength), which is comparable to the shortest duration of attosecond pulses demonstrated so far. The new method allowed to push this limitation down to 12 attoseconds  (1.2 x 10-17 s, 1/200 of the wavelength), which surpasses the atomic unit of time (24 attoseconds) by a factor of two. As the atomic unit of time marks the fastest possible time scale of processes in the outer shells of an atom, the new stabilization method will enable significant progress in the research on the fastest processes in nature.

This success strongly relied on a close collaboration with laser manufacturer Femtolasers who provided a specifically optimized laser for the joint experiment and is currently developing products based on this new method.

Ultrashort light pulse with stabilized optical phase. An ultrashort laser pulse is comprised of a few of these oscillations. (red or blue curve). Black curves: field envelope of the pulse. Maximum field strength is obtained if the field maximum coincides with the pulse center. (red curve). The newly developed method stabilizes the field pattern of the pulse. Two zoom-ins visualize smallest temporal fluctuations previously demonstrated (green frame, laser stabilization, 100 attosecond jitter) in comparison to those demonstrated with the new method of direct field synthesis (yellow frame, 12 attoseconds jitter).

Explore further: Light oscillations become visible

More information: Paper: Doi: 10.1038/NPHOTON.2010.91

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6 comments

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otto1923
not rated yet May 13, 2010
How long would a 12 attosecond glob of light be? Three feet? A half mile? Just curious.
Valentiinro
May 13, 2010
This comment has been removed by a moderator.
frajo
not rated yet May 13, 2010
How long would a 12 attosecond glob of light be? Three feet? A half mile? Just curious.
Light (in vacuum) travels 3 nm (nanometers) in 10 as (attoseconds).
Question
not rated yet May 19, 2010
quote from article
"Previously, stabilization of the position of the field maxima was only possible with a precision of about 100 attoseconds (10-16 s, corresponding to 1/20 of the wavelength), which is comparable to the shortest duration of attosecond pulses demonstrated so far. The new method allowed to push this limitation down to 12 attoseconds (1.2 x 10-17 s, 1/200 of the wavelength), which surpasses the atomic unit of time (24 attoseconds) by a factor of two."

Can anyone explain to me how light can be a photon (hf) when the pulse of the light is 1/20 the wavelength of the light?
frajo
not rated yet May 20, 2010
Can anyone explain to me how light can be a photon (hf) when the pulse of the light is 1/20 the wavelength of the light?
The momentum of the photon depends only on the wavelength and not on the length of the light pulse. The length of a light pulse being shorter than the wavelength doesn't affect the particle properties of the photons.
Question
not rated yet May 20, 2010
Can anyone explain to me how light can be a photon (hf) when the pulse of the light is 1/20 the wavelength of the light?
The momentum of the photon depends only on the wavelength and not on the length of the light pulse. The length of a light pulse being shorter than the wavelength doesn't affect the particle properties of the photons.


This is quite confusing, how can the pulse of light (or photon) be shorter than the wavelength? Granted momentum is not a problem but how can the alternating electromagnetic force carried by a light wave (or photon) be only 1/200 its wavelength?

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