Two flashes – one world record!

Admittedly, the film is not very exciting. The Brandenburg Gate depicted in the hologram does not move. And yet this is a film: about 800 billion times faster than a normal feature film. The image frequency is only 50 trillionth of a second or, in researchers' terms, 50 femtoseconds. The high resolution of 10-9 metres enables the scientists to identify the tiniest nano-scale structures in the images. Even films featuring electrons are possible using special methods.

The researchers aim at observing, understanding and, in the long term, specifically changing processes at the molecular and atomic level. Transitions from one state into another are particularly interesting, such as those taking place during ultrafast molecular processes inside cells and chemical reactions. For instance, it is possible to observe the splitting of a water molecule into its two components oxygen and hydrogen. This is why researchers do not need feature films but rather short films. They would be happy with only three images: start – reaction – conclusion. A 10-image film would count as a feature film. Technically speaking, in the future it may be possible to produce up to 100 images.

The researchers' film studio was the X-ray laser FLASH at DESY: a free-electron laser generating the ultrashort, highly intensive flashes of soft X-rays needed for taking the pictures. The 315-metre-long facility consists of three components: an accelerator accelerates the electrons to nearly the speed of light. The particles then pass through "undulators". This section consists of many hundreds of paired magnets that force the electrons into a slalom course. The thus oscillating particles emit short, strong laser flashes, which ultimately are transmitted into the experimentation room.