An international group of scientists is reporting using 25 femtosecond laser burst to capture the image of a nano size object, an advance that might allow better visualization of proteins and other bio molecules:
Lawrence Livermore National Laboratory (LLNL) scientists for the first time have validated the idea of using extremely short and intense X-ray pulses to capture images of objects such as proteins before the X-rays destroy the sample.
At the same time, the team also established a speed record of 25 femtoseconds for flash imaging…
Using the free-electron laser at Deutsches Elektronen-Synchrotron (DESY) in Hamburg, Livermore scientists, as part of an international collaboration led by LLNL’s Henry Chapman and Janos Hajdu of Uppsala University, were able to record a single diffraction pattern of a nanostructured object before the laser destroyed the sample. A Livermore-developed computer algorithm was then used to recreate an image of the object based on the recorded diffraction pattern. This “lensless” imaging technique could be applied to atomic-resolution imaging because it is not limited by the need to build a high-resolution lens. The flash images could resolve features 50 nanometers in size, which is about 10 times smaller than what is achievable with an optical microscope…
The experimental demonstration of “flash diffractive imaging” uses the first soft X-ray FEL (free electron laser) in the world located at the FLASH facility at DESY. FLASH generates high-power soft X-ray pulses by the principle of self-amplification of spontaneous emission. The pulses are 10 million times brighter than today’s brightest X-ray sources, synchrotrons. In addition, this experiment showed that it only takes a 25-femtosecond pulse duration to capture the image.
There has been a question whether the diffraction pattern recorded under these circumstances could be reconstructed to obtain undamaged sample information.
“These results could become a standardized method,” Chapman said. “This imaging could be applied at the cellular, sub-cellular and down on to single molecule scale.”