The famous bottles of whiskey are known to sell for over a million dollars. But if you are a lucky owner of such whiskey, how can you be sure that the contents of the bottle are genuine? According to a 2018 study published by the European Union’s Intellectual Property Officem Counterfeit drinks cost the UK economy more than $ 250 million annually in lost profits.

New research led by scientists at the School of Physics and Astronomy has developed a new method using a laser that can see through a bottle to analyze the contents. The challenge was to record the content signal without recording the glass signals. The research is published in the journal Analytical Methods.

The team used laser spectroscopy, a process in which laser light is directed at a substance of interest and the sample scatters the light into different colors. The exact colors of scattered light depends on the chemical composition of the substance and can therefore be used to identify a variety of materials, from bacteria, food and drink.

Instead of illuminating the bottle with a standard laser beam, researchers led by Professor Kishan Dholakia used a glass element. So they created a ring of laser light on the surface of the bottle and a tightly focused spot inside the liquid contents. Since the signal from the bottle and the signal from the liquid are in different positions, the detector can be placed to register only the signal from the liquid, which means that the contents of the bottle can be evaluated without even opening the bottle.

This approach does not require complex optical setups and therefore promises to be easily manufactured for widespread use. If whiskey isn’t to your liking, the researchers also demonstrated a method using vodka and gin. This means that in the future it will be possible to authenticate expensive alcohol without losing a drop.