Source: thznetwork.org

    British researchers say for the first time they have watched light riding through a crystal on the back of vibrations of the atomic lattice.

    Oxford University physicist Andrea Cavalleri and colleagues used X-rays in a lithium tantalate crystal to see the coordinated vibrations of its ions, linked with the passage of particles of low-frequency light called terahertz radiation.

    Lithium tantalate is a material in which an electric field induces a change in the positions of the ions that make up the crystal. The scientists say it¡¯s that behavior that creates the coupling of vibrations in the ion lattice to the oscillating electromagnetic fields of light waves.

    The lattice vibrations can be induced by shining a laser pulse onto the crystal, the scientists explained. As the lattice oscillates, it creates a fluctuating electromagnetic field that takes the form of a light polariton with a frequency close to that of the lattice vibration: at terahertz frequencies, lower than infrared, but higher than microwaves.

    The study marked the first time such polariton-linked vibrations of a crystal have been directly tracked.

    The research appears in the current issue (Aug. 10) of the journal Nature.