Experts from the nanophotonics rice University have created a unique sensor that amplifies the optical identification of molecules in 100 billion times. New tests showed that the device could accurately identify the composition and structure of individual molecules containing fewer than 20 atoms.
The project author Naomi Halas says: "the New approach offers advantages over any previously described methods. The sensor is ideal for detecting a single molecule. He will be able to identify an unknown molecule even a very small, without any prior information about its structure or composition. It is impossible, given modern technology, but this new technique has that potential."
Unique device uses Raman light. When light falls on a molecule, most of its photons bounce off, but a small portion, less than one trillionth, is absorbed and re-emitted into another energy level that differs from the initial one. Measuring and analysing these re-emitted photons through Raman light, scientists can decipher the types of atoms in the molecule and their structural organization.
Scientists from rice used several methods to enhance the Raman signal: the coherent use of two lasers and an optical amplifier of the four miniature gold nanodisks with precise diamond-shaped arrangement.