Israeli researchers find way to map tiny objects with returning light

Source: Xinhua| 2019-12-23 23:46:19|Editor: Mu Xuequan
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JERUSALEM, Dec. 23 (Xinhua) -- Israeli scientists found a method to examine and map tiny objects' structure, like viruses and organelles, using laser beams that hit the objects and scattered, Weizmann Institute of Science (WIS) in central Israel reported Monday.

After a laser beam is aimed and hit such object, the beam then spreads in a way that is affected by the object's structure.

Although some of the properties of the scattered waves are easily measured, for example intensity or wavelength, the hard part is retrieving the phase, what the waves look like at the very moment of scattering.

To deal with this problem, the WIS researchers built a unique type of laser resonator that can very quickly retrieve the missing phase and accurately solve and reconstruct the structure of the tiny object.

This system consists of two mirrors, and in between them a type of window called "hint," which is an outline of the object, obtained or estimated from a-priory knowledge.

As the light propagated back and forth through the resonator, it first identified thousands of structural configurations that could "fit" the object, according to the given hint.

However, with each pass, the hint reduced the number of possible solutions, suppressing those that were less compatible and quickly arriving at the correct structure.

This means arriving at a solution by "selection of the fittest" turns out to be over a million hours faster than with conventional computation.

The group demonstrated this principle in hard experimental situations, including imaging through diffuse materials such as biological tissue, laser beam shaping, simulations of complex magnetic materials and more.

These discoveries can serve as a basis for industrial applications to solve difficult computational problems.