Picosecond pulse-shaping for strong three-dimensional field-free alignment of generic asymmetric-top molecules

Laser pulses bring complex molecules into line

31 August 2022

A way to align complex-shaped molecules using ultrafast laser pulses has been demonstrated.

Causing molecules in a gas to align in the same direction is a critical step before imaging the molecular structure or performing certain spectroscopic measurements. This has been achieved for straight molecules and those with top-like shapes, but it has proved difficult for less symmetrically shaped molecules.

Now, a team led by researchers from the University of Hamburg in Germany has shown that it can be done using tailored picosecond (10⁻¹² second) pulses from a laser and the two-ring molecule indole.

The laser pulses were long enough to align the molecules, but short enough to allow measurements to be performed on the molecules without being affected by the laser’s electric field.

The same strategy could be used to align more-complex molecules such as vitamins and neurotransmitters, the researchers consider.

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References

1. Nature Communications 13, 1431 (2022). doi: 10.1038/s41467-022-28951-z