Synopsis: Waving, one by one

The optical equivalent of electron oscillations in periodic lattices has now been described by a fully quantum mechanical theory.
Synopsis figure

Bloch oscillations occur when electrons are driven by an external field through a periodic potential, such as that of a crystal. The phenomenon is usually interpreted in terms of the electron wave Bragg scattering off the periodic potential, causing the electron to oscillate rather than translate through the lattice. The optical analog of this effect is described in a classical picture as electromagnetic waves bouncing off a periodic structure. Writing in Physical Review Letters, Stefano Longhi of Politecnico di Milano in Italy has now formulated a fully quantum mechanical theory showing that nonclassical light consisting of only particle-like quanta can also produce optical Bloch oscillations.

Longhi considers photonic structures, where the spatial structure of the index of refraction of the material creates energy bands and band gaps analogous to those for electrons in solids, and applies a fully quantized photon field to them. He studies two situations. In the first case, photons interact with a simple singly periodic structure, and the author follows the photon number distribution as a function of distance, finding that the photons undergo Bloch oscillations just like classical particles. In a doubly periodic structure, two photon input states undergo correlated Bloch oscillations, meaning that the photons exhibit bunching and entanglement because the photons can tunnel between two energy bands. Longhi’s results may be applicable to fabricating and analyzing photonic structures useful for achieving more complex entanglements for optical quantum computing. – David Voss


Announcements

More Announcements »

Subject Areas

Optics

Previous Synopsis

Cosmology

Cosmic consistency check

Read More »

Next Synopsis

Nanophysics

Spinning on a gold atom

Read More »

Related Articles

Synopsis: Starting Fluid for Laser Fusion
Energy Research

Synopsis: Starting Fluid for Laser Fusion

A laser-based fusion experiment demonstrates that liquid fuel capsules could rectify problems encountered with ice-based fuel capsules. Read More »

Synopsis: Graphene’s Elegant Optics Explained
Graphene

Synopsis: Graphene’s Elegant Optics Explained

Theoretical calculations anchor graphene’s simple optical absorption in its two-dimensional structure instead of its cone-shaped energy bands. Read More »

Synopsis: Sharper Vision for Infrared Telescopes
Optics

Synopsis: Sharper Vision for Infrared Telescopes

Converting infrared light to visible light might boost the sensitivity of infrared telescope arrays. Read More »

More Articles